c.s 


<r>^   Sutwai 


STATE  OF  ILLINOIS 

STATE  GEOLOGICAL  SURVEY 

FRANK  W.  DEWOLF,  Director 


Cooperative  Goal  Mining  Series 

BULLETIN  18 


TESTS  ON  CLAY  MATERIALS 


AVAILABLE  IN 


ILLINOIS  GOAL  MINES 


BY 


R.  T.  STDLL  and  R.  K.  HDRSH 
Ceramics  Department,  University  of  Illinois 


ILLINOIS  GOAL  MINING  INVESTIGATIONS 

Prepared  under  a  cooperative  agreement  between  the  Illinois  State  Geological  Survey, 

the  Engineering  Experiment  Station  of  the  University  of  Illinois,  and 

the  U.  S.  Bureau  of  Mines. 


.   . 


L 


PRINTED  BY  AUTHORITY  OF  THE  STATE  OF  ILLINOIS 


ILLINOIS  STATE  GEOLOGICAL  SURVEY 

UNIVERSITY  OF  ILLINOIS 

URBANA 

1917 


The  Forty-seventh  General  Assembly  of  the  State  of  Illinois, 
with  a  view  of  conserving  the  lives  of  the  mine  workers  and  the  min- 
eral resources  of  the  State,  authorized  an  investigation  of  the  coal 
resources  and  mining  practices  of  Illinois  by  the  Department  of  Min- 
ing Engineering  of  the  University  of  Illinois  and  the  State  Geological 
Survey  in  cooperation  with  the  United  States  Bureau  of  Mines.  A 
cooperative  agreement  was  approved  by  the  Secretary  of  the  Interior 
and  by  representatives  of  the  State  of  Illinois. 

The  direction  of  this  investigation  is  vested  in  the  Director  of  the 
United  States  Bureau  of  Mines,  the  Director  of  the  State  Geological 
Survey,  and  the  Director,  Engineering  Experiment  Station,  Uni- 
versity of  Illinois,  "who  jointly  determined  the  methods  to  be  em- 
ployed in  the  conduct  of  the  work  and  exercise  general  editorial  super- 
vision over  the  publication  of  the  results,  but  each  party  to  the  agree- 
ment directs  the  work  of  its  agents  in  carrying  on  the  investigation 
thus  mutually  agreed  on. 

The  reports  of  the  investigation  are  issued  in  the  form  of  bulle- 
tins, either  by  the  State  Geological  Survey,  the  Engineering  Experiment 
Station,  University  of  Illinois,  or  the  United  States  Bureau  of  Mines. 
For  copies  of  the  bulletins  issued  by  the  State  Geological  Survey, 
address  State  Geological  Survey,  Urbana,  Illinois;  for  those  issued 
by  the  Engineering  Station,  address  Engineering  Station,  University 
of  Illinois,  Urbana,  Illinois;  and  for  those  issued  by  the  U.  S.  Bureau 
of  Mines,  address  Director,  U.  S.  Bureau  of  Mines,  Washington,  D. 
C.    (See  lis'    '      J  -*  »™'^ 


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' 


STATE  OF  ILLINOIS 

STATE  GEOLOGICAL  SURVEY 

FRANK  W.  DEWOLF.  Director 


Cooperative  Goal  Mining   Series 

BULLETIN  18 


IH.1N0  ^C!G 

SURVFY  5 

-Mm  281984 


TESTS  ON  CLAY  MATERIALS 


AVAILABLE   IN 


ILLINOIS  GOAL  MINES 


R.  T.  STULL  and  R.  K.  HURSH 
Ceramics  Department,  University  of  Illinois 


ILLINOIS   COAL   MINING   IN  V  KSTICJ  ATIONS 

Prepared  under  a  cooperative  agreement  between  the  Illinois  State  Geological  Survey, 

the  Engineering  Experiment  Station  of  the  University  of  Illinois,  and 

the  U.  S.  Bureau  of  Mines. 


PRINTED   BY   AUTHORITY   OF  THE   STATE  OF  ILLINOIS 


riLLINOIS  STATE  GEOLOGICAL  SURVEY 

UNIVERSITY  OE  ILLINOIS 

URBANA 

1917 


Mjm 


CONTENTS 


PAGE 

Introduction     9 

General   considerations 10 

Cost   of  plant 10 

Importance  of  systematic  field  examination 10 

Importance   of   laboratory  tests 11 

Characteristics  of  clays  for  various  products 11 

Common    brick 11 

Front  brick  or  pavers 12 

Hollow  ware  and  fireproofing 12 

Behavior  of  clays  during  burning 12 

General   discussion    12 

Importance  of  long  heat  range 15 

Defects  in  burned  ware 16 

Surface  pitting 16 

Scumming  due  to  calcium  sulphate  in  clay 16 

Bloating  due  to  overfiring 16 

Tests  on  samples  in  Group  1 18 

Process    employed 18 

Preparation  of   samples 18 

Slaking  tests 18 

Molding  the  briquets 19 

Oxidation   tests 19 

Tempering    water 22 

Linear  drying   shrinkage 22 

Volume    shrinkage 22 

Burning     22 

Burning   Shrinkage 23 

Porosity    23 

Tests  on  samples  in  Group  II 24 

Grinding      25 

Molding    25 

Screening    26 

Burning     26 

Results  of  tests 26 

Illinois  roof  shales  and  floor  clays 30 

Results  of  laboratory  tests  of  samples 33-128 


(5) 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  Illinois  Urbana-Champaign 


http://archive.org/details/testsonclaymater18stul 


ILLUSTRATIONS 

FIGURE  PAGE 

1.  Curves  showing  changes  in  porosity  of  paving  and  building  brick  with 

progressive  intensity  of  heat  treatment 13 

2.  Shale  and  clay  briquets  showing  excessive  surface  pitting 15 

3.  Briquets  showing  proper  burning  and  overfiring 17 

4.  Briquets  showing  progress  of  oxidation 20 

5.  Apparatus  for  saturating  briquets  in  vacuo 24 

6.  Oxidation  of  briquet  and  cylinder 25 

7.  Hand-plunger  machine  for  molding  briquets 27 

8.  Map  showing  division  of  State  into  districts  and  locations  of  samples 

collected   and   tested 29 

Graphic    illustrations    of    results   of   laboratory    tests   on    clays   and 
shales  collected  at  the  following  mines : 

9.  Barr    Brick    Company,    Streator,    and    Burlington    Paving    Brick    Com- 

pany,   Galesbu  rg 36 

10.  Illinois  Clay  Company,  Oglesby 36 

11.  St.  Paul  Coal  Company,  mine  No.  2,  Cherry 39 

12.  Spring  Valley  Coal  Company,  mine  No.  5,   Dalzell 40 

13.  Spring  Valley  Coal  Company,  mine   Xo.  5,   I  )alzel1 40 

14.  Marquette  Third  Vein  Coal  Company,  Marquette  mine,  Marquette 45 

15.  Big  Four  Wilmington  Coal  Company,  mine  No.  6,  Coal  City 46 

16.  Big  Four  Wilmington  Coal  Company,  mine  Xo.  (>,  Coal  City 46 

17.  Chicago,  Wilmington  &  Vermilion   (Oal   Company,  mine    No.    1.   South 

Wilmington 50 

18.  Chicago,  Wilmington  &  Vermilion   Coal   Company,   mine   Xo.    1,   South 

Wilmington 50 

19.  La  Salle  County  Carbon  Coal  Company,  ha  Salle  shaft,  ha  Salle 54 

20.  Matthiessen  &  Ilegeler  Zinc  Company,  M.  &  II.  mine,  ha  Salle 54 

21.  Illinois  Zinc  Company,  Black  Hollow   mine,  Oglesby 58 

22.  Oglesby   Coal   Company,    Oglesby   mine,    Oglesby 58 

23.  Gray  &  Jones  Coal  Company,  Seneca 62 

24.  Gray  &  Jones  Coal  Company,  Seneca 62 

25.  Illinois  Valley  Coal  Company,  mine  Xo.  1,  Sparland 64 

26.  Illinois  Valley  Coal  Company,  mine  No.  1,  Sparland 64 

27.  Wenona  Coal  Company,  Wenona  mine,  Wenona 69 

28.  Minonk  Coal  Company,  mine  No.  2,  Minonk 70 

29.  Minonk  Coal  Company,  mine  No.  2,  Minonk 70 

30.  Colchester  Coal  &  Manufacturing  Company,  Colchester 74 

31.  Valentine    Farm    mine,    Colchester 74 


(7) 


FIGURE  PAGE 

32.  Alden  Coal  Company,  mine  No.  7,  Matherville 76 

33.  Alden  Coal  Company,  mine  No.  7,  Matherville 76 

34.  Pryce  Coal  Company,   Coal  Valley 80 

35.  Manufacturers  &  Consumers  Coal  Company,  mine  No.  1,  Decatur 84 

36.  Decatur  Coal  Company,  Niantic  mine,  Niantic 84 

37.  McLean  County  Coal  Company,  McLean  mine,  Bloomington 88 

38.  McLean  County  Coal  Company,  McLean  mine,  Bloomington 88 

39.  Wabash  Coal  Company,  mine  No.  2,  Athens 92 

40.  Clark  Coal  &  Coke  Company,  mine  No.  2,  Peoria 92 

41.  Crescent  Coal  Company,  mine  No.  1,  Peoria 96 

42.  Colliers  Cooperative  Coal  Company,  mine  No.  1,  South  Bartonville. .  . .  98 

43.  Cantrall  Cooperative  Coal  Company,  Cantrall  mine,  Cantrall 100 

44.  Williamsville  Coal  Company,  Selbytown 100 

45.  Illinois  Midland  Coal  Company,   Sherman 102 

46.  Illinois  Midland  Coal  Company,   Sherman 102 

47.  Montour  Coal  Company,  mine  No.  400,  Springfield 106 

48.  Springfield  District  Coal  Mining  Company,  mine  No.  5,  Springfield....  108 

49.  Springfield  District  Coal  Mining  Company,  mine  No.  5,  Springfield....  108 

50.  Saline  County  Coal  Company,  mine  No.  2,  Harrisburg 110 

51.  W.  P.  Rend  Collieries  Company,  mine  No.  1,  Rend 110 

52.  Sesser  Coal  Company,  Sesser  mine,  Sesser 114 

53.  Carterville  &  Herrin  Coal  Company,  Jeffrey  mine,  Herrin 114 

54.  Brinkley  &  Miles,  Marion 116 

55.  Shoal  Creek  Coal  Company,  mine  No.  1,  Panama 116 

56.  Brilliant  Coal  Company,  Horn  mine,  Duquoin 118 

57.  Paradise  Coal  Company,  Paradise  mine,  Duquoin 118 

58.  Pioneer  Coal  Company,  Belleville 120 

59.  Mulberry  Hill  Coal  Company,  mine  No.  2,  Freeburg 120 

60.  Kolb  Coal  Company,  mine  No.  2,  Mascoutah 124 

61.  Joseph  Taylor  Coal  Company,  Taylor  mine,  O'Fallon 124 

62.  Auburn  &  Alton  Coal  Company,  Auburn 127 


(8) 


TESTS  ON  CLAY  MATERIALS  AVAILABLE  IN 
ILLINOIS  GOAL  MINES 

By  R.  T.  Stull  and  R.  K.  Hursh 


INTRODUCTION 

During  the  progress  of  field  work  under  a  cooperative  agreement 
between  the  State  Geological  Survey,  the  U.  S.  Bureau  of  Mines,  and 
the  Engineering  Experiment  Station  of  the  University  of  Illinois,  it 
was  decided  to  determine  the  possibility  of  using  in  the  clay-working 
industry  floor  clays  and  roof  shales  from  Illinois  coal  mines.  Arrange- 
ments were  made  by  which  the  Geological  Survey  would  furnish  the 
samples  and  the  Department  of  Ceramic  Engineering1,  University  of 
Illinois,  would  make  the  necessary  physical  and  burning  tests. 

During  the  first  season,  the  collection  of  samples  was  made  inci- 
dental to  the  regular  field  work  of  the  geologists,  and  some  actual 
sampling  was  done  by  the  mining  companies.  Twenty-three  samples 
were  collected  and  tested  during  the  winter  of  1912-13  and  designated 
as  Group  1.  The  desirability  of  systematic  sampling  was  recognized, 
and  during  the  summer  of  1913  one  man's  entire  attention  was  given 
to  this  work.  Eighty-three  samples  were  collected,  and  in  this  report 
they  are  designated  as  Group  II.  The  tests  on  this  series  were  similar 
to  those  for  Group  I,  but  more  efficient  means  were  devised  during 
the  second  season  for  grinding  and  molding  the  material. 

l>y  way  of  summary  it  may  be  said  that  49  samples  proved  to  be 
worthless,  5  were  of  questionable  value,  and  52  were  found  adapted 
to  the  manufacture  of  a  number  of  clay  products.  Common  brick  can 
be  made  from  the  material  represented  by  52  counties;  39  were  usable 
for  front  brick;  29  for  hollow  ware;  6  for  paving  brick;  6  for  lire- 
proofing;  1  for  enameled  brick  and  terra  cotta ;  2  for  stoneware  and 
sewer  pipe  and  2  for  No.  2  fire  brick.  These  materials  were  not  from 
existing  clay  pits  or  clay  mines,  but  from  coal  mines,  where  clay  mater- 
ials are  not  now  utilized. 

Before  considering  the  results,  it  is  desirable  to  give  attention 
to  the  general  factors  that  control  the  availability  of  clays  and  shales 
as  successful  ceramic  materials. 


'The  Graduate  School  of  the  University  of   Illinois  cooperated  by  contributing  money 
to  be   used   in  connection    with   the   tests. 


(9) 


10  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

GENERAL  CONSIDERATIONS 
Cost  of  Plant 

Under  most  favorable  conditions  of  low  cost  of  raw  material 
and  labor,  it  is  not  advisable  to  install  a  modern  brick  plant  equipped 
with  a  permanent  dryer  and  kilns  for  a  daily  capacity  of  less  than 
10,000  to  15,000  brick.  An  exception  to  this  is  made  where  the  clay 
produces  a  high-grade  product  commanding  a  high  market  price.  The 
cost  of  building  a  modern  plant  is  a  variable  factor  governed  by  local 
conditions  and  by  the  kind  of  material  and  equipment  used  in  its  con- 
struction. A  well-known  brick-works  engineer  has  said  that  it  requires 
approximately  as  many  dollars  to  build  a  modern  brick  plant  as  is  the 
daily  capacity  of  the  plant  in  bricks.  It  would,  therefore,  require 
approximately  $15,000  to  build  a  modern  plant  with  a  daily  capacity 
of  15,000  brick.  The  rule  is  by  no  means  rigid  and  may  be  regarded 
merely  as  an  approximate  guide. 

Many  clay-working  enterprises  have  encountered  serious  troubles, 
and  some  have  even  failed  due  simply  to  the  failure  of  making  a  thor- 
ough previous  investigation  of  the  clay,  a  very  important  step  that 
should  be  assigned  to  a  competent  ceramic  engineer  or  expert  in  order 
to  determine  quantity  and  quality  of  the  material.  Too  often  this  is 
given  minor  consideration  or  is  left  in  the  hands  of  incompetents. 
It  is  not  advisable  to  build  a  modern  plant  unless  there  is  available 
sufficient  clay  of  satisfactory  quality  to  continue  the  plant  in  operation 
for  a  period  of  more  than  ten  years.  To  make  a  thousand  brick  of 
standard  American  size  requires  approximately  two  cubic  yards  of 
clay.  A  plant  making  15,000  brick  per  day  would  require  9,000  cubic 
yards,  or  approximately  13,500  tons  of  clay  per  year  of  300  working 
days. 

Importance  of  Systematic  Field  Examination 

Since  clays  are  not  definite  compounds,  but  are  for  the  most  part 
"mixtures  of  minerals",  they  may  vary  considerably  in  composition 
from  point  to  point  in  the  deposit.  The  composition  may  be  very 
uniform  horizontally  over  a  considerable  area,  whereas  the  composi- 
tion in  a  vertical  direction  is  likely  to  show  abrupt  changes  due  to 
the  manner  in  which  the  clay  had  been  laid  down,  or  to  unconformi- 
ties. Abrupt  changes  also  occur  horizontally  where  faulting  is  en- 
countered. 

Too  much  care  can  not  be  exercised  in  selecting  the  clay  samples 
for  tests.  Fair  average  samples  of  the  deposit  should  be  taken  at  a 
number  of  places  over  the  property.  If  two  or  more  strata  of  different 
appearances  occur,  samples  of  these  should  be  taken  and  tested  sepa- 


CHARACTERISTICS  OF  CLAYS  11 

rately.  Outcrops  have  been  subjected  to  long  periods  of  weathering 
and  have  been  more  or  less  purified  by  the  breaking  down  of  mineral 
matter  and  the  leaching  out  of  soluble  salts  by  rains.  The  weathered 
portion  of  a  shale  will  frequently  give  very  good  results  under  tests, 
whereas  the  inner  unweathered  shale  may  prove  very  troublesome. 
Since  the  weathered  portion  is  only  a  negligible  part  of  the  deposit 
as  a  whole,  it  should  be  rejected  in  selecting  the  samples,  and  only 
the  unweathered  portions  taken. 

Importance  of  Laboratory  Tests 
It  is  a  well-known  fact  that  laboratory  tests  on  small-sized  samples 
do  not  furnish  conclusive  evidence  as  to  the  practical  value  of  a  clay 
for  manufacturing  purposes.  The  reason  for  this  lies  in  the  fact  that 
factory  conditions  can  not  be  duplicated  in  the  laboratory.  Neverthe- 
less, the  laboratory  tests  are  essential  in  that  they  acquaint  one  with 
the  physical  behavior  of  clays  and  point  out  whether  they  have  com- 
mercial possibilities  or  not.  If  a  clay  is  so  inherently  bad  as  to  be  an 
impossible  raw  material  for  the  manufacture  of  clay  wares,  this  will 
be  indicated  by  the  laboratory  tests.  The  laboratory  tests  will  show 
also  whether  a  clay  is  safe  for  making  vitrified  ware  and  will  show 
to  what  class  of  products  the  clay  is  best  suited. 

If  the  laboratory  tests  indicate  that  a  clay  is  capable  of  producing 
a  desirable  product  without  developing  serious  difficulties  which  might 
be  encountered  during  the  process  of  manufacture,  then  the  results 
from  the  laboratory  would  warrant  the  further  testing  of  the  clay  in 
a  large  enough  quantity  to  approach  factory  conditions  as  closely  as 
possible. 

CHARACTERISTICS  OF  (LANS  FOR  VARIOUS  PRODUCTS 

Common  Brick 
Common  brick  may  be  manufactured  by  either  the  soft-mud  or 
the  stiff-mud  process — the  former  is  best  adapted  to  the  rather  plastic 
surface  clays,  whereas  the  latter  process  is  most  generally  used  in 
working  shales.  To  produce  a  brick  of  satisfactory  structure  and  ap- 
pearance by  the  stiff-mud  process  requires  a  clay  of  an  intermediate  de- 
gree of  plasticity.  Short  clays,  or  those  of  very  low  plasticity,  have  too 
little  bonding  strength  in  the  stiff-mud  condition  to  withstand  the 
strains  produced  in  passing  through  the  die  of  the  ordinary  brick 
machine.  The  issuing  column  is  likely  to  be  rough  or  torn  and  fre- 
quently cracked.  The  ware  is  usually  too  fragile  to  be  handled  with- 
out breaking,  and  the  dried  body  may  crumble  easily.  Clays  of  very 
high  plasticity  will  laminate  and  tear  at  the  corner  as  the  column 
issues   from  the  die.     Such  materials  usually  produce  a   strong  body 


12  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

but  show  high-drying  shrinkage,  and  the  ware   is  likely  to  warp  or 
crack  unless  dried  very  carefully. 

Front  Brick  or  Pavers 
For  front  brick  or  pavers  it  is  even  more  necessary  that  the  clay 
be  capable  of  forming  a  smooth  column  free  from  excessive  lamina- 
tion, and  that  it  withstand  the  necessary  handling  both  in  the  plastic 
and  dried  condition  without  breaking  or  crumbling.  It  must  likewise 
dry  safely  without  undue  shrinkage  and  without  warping  or  cracking. 

Hollow  Ware  and  Fireproofing 
Clays  for  the  manufacture  of  hollow  ware  and  fireproofing  must 
have  a  greater  degree  of  plasticity  than  the   minimum   required   for 
brick,  in  order  that  they  may  be  molded  properly.     They  must  dry 
without  cracking. 

BEHAVIOR  OF  CLAYS  DURING  BURNING 
General  Discussion 

Materials  which  possess  satisfactory  working  and  drying  prop- 
erties must  next  be  judged  upon  the  basis  of  their  burning  behavior. 
The  effects  of  carbon  in  its  various  forms,  pyrite,  and  ferrous  iron 
in  the  oxidization  and  vitrification  of  clays  will  be  discussed.  Clays 
which  may  be  oxidized  easily  require  much  shorter  periods  of  burning 
than  those  which  give  greater  difficulty.  This  is  an  important  element 
in  the  cost  of  manufacture.  Materials  containing  large  amounts  of 
carbon,  pyrite,  or  ferrous  iron  or  which  become  dense  at  low  tempera- 
tures and  therefore  greatly  retard  the  process  of  oxidization  may  be 
regarded  as  unsuitable  for  manufacturing  purposes.  The  oxidization 
tests  made  in  the  present  investigation  show  the  comparative  ease  or 
difficulty  of  burning  the  various  samples  in  this  period  and  the  relative 
danger  of  bloating  due  to  incomplete  oxidization.  Clays  that  were 
completely  oxidized  in  a  few  hours  should  give  no  great  trouble  in 
burning,  but  those  that  showed  a  black  core  of  any  considerable  size 
at  the  end  of  the  ten-hour  period  may  be  eliminated  as  commercial 
possibilities  for  any  type  of  ware. 

An  exception  may  be  noted  in  clays  which  remain  quite  porous 
at  temperatures  well  above  those  usually  used  for  oxidization  and 
do  not  vitrify.  In  burning  some  materials  of  this  sort,  ground  coal 
is  actually  added  to  the  clay  to  aid  in  the  burning  of  the  ware.  In 
such  cases  only  porous  common  brick  may  be  made. 

Clays  that  crack  or  warp  badly  in  burning  can  not  be  used  for 
any  ware  save  possibly  common  brick,  but  these  should  be  discarded 
where  any  better  material  is  available. 


BEHAVIOR  OF  CLAYS  DURING   BURNING 


13 


Pitting  due  to  granules  of  iron  compounds  or  due  to  the  slaking 
of  lime  lumps  in  the  burned  clay  when  exposed  to  moist  atmosphere 
is  undesirable  in  any  ware  but  does  not  eliminate  a  clay  as  a  possibility 
for  common  brick  and  hollow  ware  unless  it  be  excessive.  Front  brick 
and  pavers  must  be  sound  and  free  from  such  defects. 


06  M  ^2  5  3  5 

TEMPERA  TV  RES  EXPRESSED  IN  CONES 

Fig.  1. — Curves  showing  changes  in  porosity  of  paving  and  building-brick 
clays  with  progressive  intensity  of  heat  treatment. 

The  most  important  criterion  in  determining  the  commercial 
availability  of  a  clay  lies  in  a  proper  interpretation  of  the  porosity- 
temperature  relation  in  burning.  An  excellent  discussion  of  this  has 
been  given  by  Purdy.2  The  decrease  in  porosity  indicates  the  progress 
of  hardening  and  vitrification  of  the  clay,  the  range  of  safe  burning 

-J'urdy,  Ross  ('.,  Paving  brick  and  paving  brick  clays  of  Illinois:  111.  State  Geol. 
Survey    Bull.  9,   1908. 


14  CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 

temperatures,  and  the  point  of  overburning.  It  will  be  noted  in  the 
curves  that  many  of  the  clays  show  an  abrupt  drop  in  porosity  within 
a  short  range  of  burning  temperature  and  a  subsequent  increase  in 
porosity  after  the  minimum  has  been  reached.  The  rapid  decrease 
in  pore  space  is  due  to  sudden  fluxing  action  in  the  clay.  The  rise  in 
the  porosity  curve  indicates  overburning  and  bloating.  Where  bloating 
quickly  succeeds  an  abrupt  drop  in  porosity,  the  material  may  not  be 
safely  used  for  vitrified  wares,  such  as  paving  brick.  The  general 
shape  of  porosity  temperature  curves  for  various  classes  of  brick  has 
been  shown  by  Purely  in  figure  32. 2  It  is  noted  that  suitable  paving- 
brick  clays  must  not  vitrify  at  too  low  a  temperature  and  must  have 
a  sufficient  range  of  burning  temperatures  at  low  porosity  to  permit 
proper  burning  within  the  limits  of  temperature  difference  in  the  com- 
mercial kiln,  2-4  cones.  The  ultimate  criterion  for  this  class  of  ware 
must  be  the  toughness  test,  but  the  burning  behavior  test  (fig.  1) 
serves  to  eliminate  a  majority  of  the  undesirable  materials. 

Clays  that  will  vitrify  without  serious  danger  of  overburning  but 
that  are  not  suitable  for  first-class  pavers  will  show  porosity  curves 
in  Area  II.  These  are  suitable  for  vitrified  front  brick  and  hollow 
ware. 

Clays  having  a  short  heat  range  and  which  overburn  easily  are 
found  in  Area  III.  These  are  suitable  only  for  porous  products  such 
as  common  brick,  unverified  front  brick,  or  porous  hollow  ware. 

The  materials  showing  porosity  curves  lying  in  Area  IV  should 
not  be  considered  for  manufacturing  purposes,  since  they  are  likely 
to  overburn  and  bloat  even  while  very  porous. 

Color  is  not  an  important  factor  in  common  brick  and  hollow 
blocks  and,  to  a  minor  degree  only,  in  draintile.  Paving  brick  are 
less  salable  if  badly  scummed  by  soluble  sulphates.  Front  brick  must 
be  of  good  color  and  free  from  scumming  ingredients.  Scumming 
may  be  prevented,  if  not  too  serious,  by  the  use  of  barium  compounds, 
but  where  it  showed  excessively  in  a  material  in  these  tests  the  clay 
has  not  been  considered  available  for  front  brick  manufacture. 

Summarizing  the  above  remarks,  we  may  list  the  following  gen- 
eral requirements  for  the  various  wares  : 

Paving-brick  clays  should  have  a  fair  plasticity,  should  not  lam- 
inate seriously,  should  dry  safely  and  oxidize  easily.  They  should  not 
vitrify  too  easily  and  should  show  a  good  heat  range  at  low  porosity. 

Front  brick  require  clays  of  good  molding  and  drying  properties, 
easy  of  oxidation,  of  good  color,  and  a  fair  range  of  burning  tem- 
perature at  which  uniform  colors  can  be  obtained. 


2Purdy,    Ross    C,    Paving   brick   and    paving   brick    clays   of    Illinois:    111.    State    GeoL 
Survey    Bull.    9,    1908. 


BEHAVIOR  OF  CLAYS   Dl'RIXG    BURNING 


15 


Common  brick  may  be  made  from  clays  of  fair  plasticity  and 
working  properties  if  the  drying  behavior  is  good,  if  they  oxidize  in 
a  reasonable  length  of  time  and  produce  a  hard  sound  ware  without 
too  great  danger  of  overburning. 

The  manufacture  of  hollozc  ware  requires  somewhat  higher  plas- 
ticity than  would  be  necessary  for  brick,  but  other  properties  are 
about  the  same. 


Fig.  2. — Briquets  of  a  red  shale  (sample  50)  and  a  bluff  clay  (sample  58) 
showing  excessive  surface  pitting. 

[mportance  of  Long  Heat  Range 
The  differences  in  temperature  between  the  hottest  and  coolest 
parts  of  a  kiln  are  influenced  by  the  design  of  the  kiln  and  the  man- 
ner in  which  it  is  fired  and  controlled.  The  differences  in  temperature 
within  commercial  kiln  chambers  have  been  found  to  vary  from  20' 
C  to  as  high  as  80°  C,  or  from  one  to  four  cones.  For  this  reason 
it  is  essential  that  a  clay  should  have  a  long  heat  range,  so  that  ware 
from  different  parts  of  the  kiln  may  be  uniform  in  color,  size,  and 
density. 

Lime,  through  its  vigorous  fluxing  action  when  uniformly  dis- 
tributed, imparts  to  clay  a  short  heat  range.  The  temperature  interval 
between  vitrification  and  fusion  is  so  short  that  it  is  dangerous  to 
attempt  the  manufacture  of  a  vitrified  product  from  a  calcareous  clay. 
However,  clays  of  this  type  may  be  valuable   for  the  manufacture  of 


16  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

the  more  common  porous  products,  such  as  common  brick  and  hollow 
blocks. 

Defects  in  Burned  Ware 
surface  pitting 

Surface  pitting,  or  "popping  out"  as  it  is  sometimes  called,  is 
caused  by  granules  near  the  surface  which  expand  and  force  out 
flat,  irregularly  shaped  chips  from  the  surface  leaving  the  granules  ex- 
posed (fig.  2).  There  are  two  distinct  types  of  surface  pitting.  One 
kind  occurs  during  the  burning  and  is  caused  by  granules  of  pyrite, 
iron  carbonate,  or  fragments  of  concretions  composed  of  a  mixture 
of  calcium  and  iron  carbonates.  The  "popping  out"  is  due  to  the 
peculiar  expansion  of  these  granules  during  the  oxidation  period  and 
occurs  at  or  below  700°  C  leaving  a  black  hard  grain  exposed. 

In  a  number  of  trials  drawn  from  the  kiln  soon  after  popping 
occurred  the  black  granules  were  strongly  attracted  by  a  magnet,  indi- 
cating the  presence  of  the  magnetic  oxide  of  iron  (Fe304).  If  left 
in  the  kiln  for  a  considerable  period  of  time,  they  lost  this  property. 

The  second  type  of  pitting  does  not  occur  until  some  time  after 
the  ware  has  been  removed  from  the  kiln  and  is  due  to  the  subsequent 
hydration  and  expansion  of  lime  granules.  The  granules  thus  exposed 
are  usually  white  and  very  friable. 

Where  surface  pitting  is  profuse,  it  bars  a  clay  as  a  desirable 
raw  material  for  smooth-faced  front  brick,  but  would  not  be  consid- 
ered a  serious  defect  in  common  brick  or  hollow  ware. 

SCUMMING  DUE  TO   CALCIUM    SULPHATE   IN    THE   CLAY 

Approximately  one  part  of  calcium  sulphate  is  soluble  in  40  parts 
of  water.  When  calcium  sulphate  is  present  in  a  clay  either  as  such 
or  in  the  form  of  gypsum,  part  of  it  is  dissolved  and  is  carried  to  the 
surface  during  drying  and  deposited  as  a  "scum"  or  "efflorescence". 
The  salt  is  comparatively  stable  and  is  practically  unaffected  during 
the  burn  and,  unless  the  clay  is  burned  hard  enough  to  fuse  it  with 
the  clay,  causes  a  discolored  or  scummed  product.  Scumming  if  not 
excessive  is  not  considered  a  serious  defect,  since  it  can  be  overcome 
by  the  addition  of  barium  in  the  form  of  the  carbonate,  hydrate,  chlo- 
ride, or  fluoride. 

BLOATING    DUE    TO    OVERFIRING 

There  are  two  different  kinds  of  bloating.  One  kind  is  the  result 
of  improper  oxidation  as  previously  described.  The  second  kind 
occurs  after  oxidation  has  been  completed  and  is  due  to  the  evolu- 
tion  of  occluded  gases,  to  violatilization  of  some   constituent  of   the 


P.EILWIOR  OF  CLAYS   DURIXC.    BURNING 


17 


clay  or  to  gas  evolution  caused  by  dissociation,  as  for  example,  the 
evolution  of  sulphur  dioxide  by  the  reduction  and  dissociation  of  a 
sulphate.  In  this  condition  the  clay  is  said  to  be  overtired  (fig.  3). 
Bloatirg  due  to  incomplete  oxidation  is  characterized  by  a  black 
spongy  core  with  a  light-colored,  dense  outer  shell.  In  the  case  of 
overburning  the  color  is  generally  uniformly  gray,  red,  or  brown,  and 
the  material  is  spongy  throughout. 


a                       b 

Fig.  3. —  Briquets  showing  proper  burning  and  overfiring. 

There  are  three  distinct  types  of  bloating  due  to  overfiring:3 

1.  Clays    developing    a    vesicular    structure    when    their    normal    porosities 

are  still  high  and  before  vitrification  begins. 

2.  Clays    developing   a    vesicular   structure    simultaneously    with    the    prog- 

ress of  vitrification. 

3.  Clays  that  do  not  develop  a  vesicular  structure  until  more  or  less  of  a 

temperature  interval  has  elapsed  after  they  have  Become  vitrified. 

During  the  progress  of  burning  clays,  there  is  a  decrease  in 
porosity  and  an  increase  in  shrinkage  with  rise  in  temperature  after 
900°  C  is  passed.  When  bloating  begins,  there  is  an  increase  in 
porosity  and  a  negative  shrinkage  or  apparent  increase  in  volume. 
In  clays  of  the  first  type  the  point  at  which  bloating  begins  is  indi- 
cated by  a  change  in  the  direction  of  the  porosity  curve.      In  clays  of 


8Bleininger,    A.    \\,   and    Montgomery,    E.     I  ., 
>f  clays:   U.   S.    Bureau  <»f  Standards  Tech.    Paper  1. 


feet   of 
915. 


the    structu 


18  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

the  second  and  third  types  the  pores  developed  by  gas  evolution  are 
sealed  due  to  vitrification,  hence  they  can  not  be  measured  by  satura- 
tion in  vacuo,  and  no  change  in  direction  of  the  porosity  curve  is  indi- 
cated. However,  in  all  three  types  the  point  at  which  bloating  begins 
is  indicated  by  the  change  in  direction  of  the  shrinkage  curve. 

Clays  of  the  first  and  second  types  are  impossible  raw  materials 
for  the  manufacture  of  vitrified  wares  but  may  be  valuable  for  the 
manufacture  of  porous  products  if  burned  at  a  safe  limit  below  the 
point  where  bloating  occurs.  For  a  vitrified  product  it  is  essential 
that  the  clay  should  have  a  good  heat  range  or  temperature  interval 
between  the  point  at  which  it  becomes  vitrified  and  that  at  which  it 
fails  either  by  bloating  or  by  fusion. 

TESTS  ON  SAMPLES  IN  GROUP  I 
Process  Employed 

With  few  exceptions  the  workable  shales  are  admirably  adapted 
to  the  "stiff-mud"  or  plastic  process  of  manufacture  and  are  valuable 
raw  materials  for  making  structural  materials  such  as  building  and 
paving  brick,  hollow  blocks,  draintile,  sewer  pipe,  and  a  variety  of 
similar  products.  The  vast  majority  of  shale  brick  are  made  by  the 
stiff-mud  process,  and  this  is  the  only  practicable  process  by  which 
hollow  blocks  and  pipe  are  made. 

Accordingly  the  plastic  process  was  employed  in  the  following 
tests.  In  this  work  two  groups  comprising  108  different  samples  were 
tested.  The  work  on  the  first  group  was  nearly  completed  before  the 
second  group  was  received.  The  manner  of  testing  the  two  groups 
was  the  same  with  the  exception  of  a  few  changes  which  will  be 
pointed  out  under  Group  II. 

Group  I  comprised  twenty-five  samples ;  No.  24  from  Galesburg 
and  No.  25  from  Streator  are  well-known  shales  which  have  been 
successfully  employed  for  years  in  the  manufacture  of  building  and 
paving  brick  and  were  included  for  comparative  purposes. 

Preparation  of  the  Samples 
The  samples,  consisting  of  approximately  50  pounds  each,  were 
examined  to  detect  the  presence  of  gypsum,  pyrite,  carbonaceous  mat- 
ter, and  carbonates  of  iron  and  lime.  A  two-pound  representative 
sample  was  set  aside  for  future  reference,  and  the  remainder  reduced 
in  a  jaw  crusher,  passed  through  the  ten-mesh  screen  and  thoroughly 
mixed  ready  for  tempering  and  molding  the  briquets. 

Slaking 
Many   shales   and   fire   clays  possess   the   property   of    slaking   in 
water.     Some  slake  rapidly  and  yield  a  fine-grained  plastic  mass  with 


TESTS  ON  SAMPLES  IN  GROUP  I  19 

very  little  or  no  granular  residue.  Most  of  these  are  soft  or  of  medium 
hardness,  rather  fine  grained,  very  plastic  and  mold  readily  in  either 
a  dry  or  lubricated  die.  They  generally  show  a  high  drying  shrinkage 
and  may  warp  or  even  crack  in  drying. 

Another  class  of  shales  is  medium  hard  to  hard ;  these  slake 
slowly  to  a  mixture  of  coarse  granular  material  with  a  more  or  less 
fine  plastic  portion.  In  general  they  show  medium  to  good  plasticity, 
mold  without  serious  trouble,  show  a  moderate  drying  shrinkage,  and 
dry  safely. 

A  third  class  is  more  or  less  hard,  coarse,  somewhat  granular, 
perhaps  sandy,  and  may  contain  numerous  mica  flakes  and  shell  fossils. 
Shales  of  this  class  do  not  slake  appreciably  and  show  indifference 
to  disintegration  on  weathering.  When  ground  and  tempered  they 
show  poor  plasticity,  mold  with  difficulty  in  the  die,  have  very  low 
drying  shrinkage,  and  dry  safely.  When  a  plastic  clay  or  shale  is 
added  to  them,  they  frequently  produce  most  excellent  ware. 

In  order  to  obtain  an  approximate  idea  of  the  slaking  behavior  of 
the  shales  under  tests,  a  100-gram  sample  of  each  was  weighed  from 
the  2-pound  sample,  rejecting  all  fragments  less  than  one-fourth  inch 
in  diameter.  This  was  dried  at  60°  C  for  ten  hours,  placed  in  a  granite 
pan  and  covered  with  distilled  water,  and  the  rate  of  slaking  at  room 
temperature  observed  at  intervals  over  a  period  of  7  days.  The  obser- 
vations were  made  every  hour  for  the  first  five  hours,  then  every  two 
hours  for  the  next  ten  hours,  and  finally  every  twelve  hours  to  the 
end  of  the  period. 

Molding  the  Briquets 

The  ground  and  screened  samples  were  prepared  for  molding  the 
briquets  by  kneading  and  wedging  the  samples  with  sufficient  water 
added  to  give  best  working  plasticity.  The  samples  after  tempering 
were  placed  in  a  moist  chamber  for  24  hours  to  produce  uniformity 
of  moisture  content.  Briquets  of  two  different  sizes  were  made.  For 
oxidation  tests,  trials  l-)4" x  1-H" x  3V? "  were  hand  molded  and 
repressed.  For  determining  tempering  water,  volume  shrinkage,  linear 
drying  and  burning  shrinkages,  porosity,  tempering  range,  and  color, 
briquets  l"x  l"x  3J4"  were  also  hand  molded  and  repressed.  All 
briquets  were  dried  in  the  open  air  at  room  temperature  (about  70°  F  ). 

(  )xidation  Tests 

During  the  process  of  burning  red  and  buff  clays,  it  is  necessary 
to  burn  out  the  carbon  and  sulphur  and  to  convert  the  ferrous  iron  to 
the  ferric  form  before  the  temperature  can  be  raised  safely  and  the 
ware  vitrified.     This  process  is  called  oxidation  and  should  be  carried 


20 


CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 


out  within  a  temperature  interval  in  which  the  ware  is  at  its  maximum 
porosity  so  as  to  allow  the  ingress  of  oxygen  from  the  kiln  atmosphere 
and  the  egress  of  gases  due  to  distillation  and  combustion.  If  the 
temperature  of  the  kiln  is  raised  to  the  vitrification  stage  before  oxida- 
tion is  complete,  a  black-cored  or  even  bloated  product  will  be  the 
result. 


Fig.  4. — A  clay  high  in  pyrite  and  carbon  showing  progress  of  diminishing 
black  core  during  oxidation.  The  trials  were  drawn  from  the  kiln  at  one-hour 
intervals. 

Under  practical  working  conditions  it  has  been  found  that  the 
best  range  in  which  to  hold  the  kiln  until  oxidation  is  complete  lies 
between  600°  C  and  900°  C.4  The  most  troublesome  materials  during 
oxidation  are  bituminous  matter,  sulphur  in  the  form  of  pyrite,  ferrous 
oxide,  and  ferrous  carbonate.  As  long  as  any  carbon  or  combustible 
sulphur  is  present,  the  iron  remains  in  the  ferrous  form  and  is  evi- 
denced by  the  resulting  black  core  surrounded  by  an  oxidized  outer 
shell  of  light  salmon  or  buff  color  (fig.  4). 

According  to  Wells5  pyrite  is  dissociated  at  two  different  tempera- 
tures one  molecule  of  sulphur  coming  off  at  400°  C,  and  the  second  re- 
maining until  about  900°  C.  In  the  tests  of  the  following  shales  it 
was  observed  that  the  pyrite  could  be  completely  dissociated  and  the 
iron  converted  to  the  ferric  form  if  the  temperature  of  the  kiln  were 
held  long  enough  at  650°  C.  However,  the  rate  of  oxidation  increases 
rapidly  with  increase  of  temperature  so  long  as  the  clay  remains  suf- 
ficiently porous  to  allow  the  reaction  to  go  on  freely. 


4Orton,  E.,  The  role  played  by  iron  in  the  burning  of  clay:  Trans.  Am.  Cer.  Soc. 
vol.    5,   p.   404,   1903. 

•"'Wells,  II.  B.,  A  method  of  overcoming  the  sulphur  problem:  Trans.  Am.  Cer.  Soc. 
vol.    11,   p.   94,    1909. 


TESTS  ON   SAMPLES  IN  GROUP  I  21 

Many  "Coal  Measures"  shales  are  high  in  sulphur  and  bituminous 
matter.  Commonly  they  contain  as  much  as  4  per  cent  of  bituminous 
matter  and  2  per  cent  of  pyrite.  The  average  periodic  brick  kiln  holds 
approximately  100,000  American-size  brick.  The  average  weight 
per  thousand  dry  brick  is  3  tons.  In  15  pounds  of  pyrite  are  7  pounds 
of  iron  and  8  pounds  of  sulphur.  If  a  shale  contains  4  per  cent  of 
bituminous  matter  and  2  per  cent  of  pyrite,  a  kiln  holding  100,000 
brick  made  from  the  shale  would  contain  12  tons  of  fuel  as  "coaly 
matter"  and  over  3  tons  as  combustible  sulphur. 

If  a  shale  of  this  character  vitrifies  at  a  comparatively  low  tem- 
perature, it  becomes  a  very  troublesome,  if  not  a  disastrous  material 
to  handle.  When  the  temperature  of  the  kiln  rises  to  the  ignition 
point,  the  volatile  gases  take  fire  on  the  exposed  surfaces  of  the  brick 
and  raise  the  temperature  rapidly.  The  sudden  rise  in  temperature 
vitrifies  the  outside  shell  of  the  brick,  closes  the  pores,  prevents  the 
escape  of  gases,  and  causes  bloating  not  unlike  the  resulting  action 
of  yeast  in  bread. 

In  order  to  prevent  bloating  it  is  necessary  to  hold  the  tempera- 
ture of  the  kiln  down  to  a  safe  limit  below  the  vitrification  temperature 
until  the  combustible  matter  has  been  eliminated.  ( )rton6  recommends 
a  method  of  kiln  control  which  has  proved  very  effective.  Briefly  it 
consists  of  the  following : 

If  a  clay  is  rather  refractory  and  remains  porous  at  a  compara- 
tively high  temperature,  the  evolution  and  combustion  of  the  volatile 
matter  may  progress  without  causing  serious  trouble. 

1.  Fire  the  kiln  normally  until  the  evolving  gases  ignite.    This  is  indicated 

hy  a  sudden  brightening  or  glow  in  the  kiln  chamber. 

2.  At  this   point,   draw   the   fires,   lower   the   damper,   and   seal   up  the   fire 

boxes  and  kiln  to  exclude  air  and  to  allow  the  evolution  of  the  gases 

to  progress  slowly  without  increasing  the  temperature. 

3.  As  soon  as  the  danger  is  passed  the  "glow"  will  diminish  and  the  kiln 

temperature    drop.      At    this    point,    raise    the    damper,    open    the    lire 
boxes,  and  proceed  with  the  tiring  normally. 

To  obtain  a  comparison  of  the  oxidizing  behaviors  of  the  different 
clay  samples  the  following  oxidation  test  was  made.  Briquets  were 
placed  in  a  down-draft  kiln,  the  temperature  raised  gradually  to  650° 
C,  and  held  constant.  As  soon  as  this  temperature  was  attained  a 
trial  piece  of  each  clay  was  drawn  and  further  specimens  were  drawn 
every  hour  for  a  period  of  9  hours.  As  soon  as  the  trials  were  taken 
from  the  kiln  they  were  covered  with  sand,  allowed  to  cool  and  the 
areas  of  the  oxidized  part  and  the  black  core  of  a  cross-section  meas- 
ured with  a  planimeter.     (See  figure  1  and  time-rate  oxidation  curves.) 


flOp.  cit.,  pp.  395-396. 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


Tempering  Water 

When  water  is  added  to  clay,  the  mass  increases  in  volume,  and 
on  drying  a  corresponding  shrinkage  takes  place.  The  amount  of 
water7  necessary  to  add  to  a  clay  in  order  to  make  it  sufficiently  plastic 
for  molding  varies  with  different  clays.  The  higher  the  plasticity 
and  the  finer  the  grain,  the  more  water  is  required  to  temper  a  clay 
in  order  to  make  it  "moldable"  and  the  greater  is  the  shrinkage  on 
drying.  The  amount  of  water  required  to  temper  a  clay  to  the  proper 
consistency  for  molding  was  determined  by  taking  the  weight  of  five 
freshly  molded  briquets,  drying  them  at  100°  C,  cooling,  and  weighing. 
The  percentage  of  water  required,  based  upon  the  dry  weight  of  the 
clay,  is  calculated  from  the  following  formula : 

A  —  B 

x  100  —  %  tempering  water, 

B 

Where  :  A  =  weight  of  freshly  made  briquet, 
B  =  weight  of  dry  briquet. 

Linear  Drying  Shrinkage 

The  linear  drying  shrinkage  was  determined  by  measuring  the 

freshly   molded   briquet   with   Vernier   calipers   and   again   measuring 

after  drying.     The  percentage  of  linear  drying  shrinkage  based  upon 

dry  length  was  calculated  from  the  following  formula : 

U  —  U 

x  100  —  %  linear  drying  shrinkage, 

L2 

Where :  Li  =  molded  length, 
L2  =  dry  length. 

Volume  Shrinkage 
The  volume  shrinkage  in  drying  was  determined  by  the  kerosene 
oil  immersion  method,  using  a  modification  of  the   Seger  volumeter 
and  the  calculations  were  made  according  to  the  formula : 

V!  —  V. 

100  —  %  volume  shrinkage. 


V2 
Where  :  Vi  —  volume  of  freshly  molded  briquet, 

V2  =  volume  of  the  briquet  dried  at  100°   C. 

Burning 

Since  a  number  of  the  shales  are  very  fine  grained  and  contain 

carbonaceous  matter  and  pyrite,  they  are  slow  and  difficult  to  oxidize. 

To  insure  thorough  oxidation  of  the  trials  and  to  save  time  in  the 

subsequent   burns,    all    burning   trials   were    first    placed    in    the    kiln, 


'Sometimes   erroneously   called   "water   of  plasticity." 


TESTS  ON   SAMPLES  IN  GROUP  II 


23 


oxidized  at  650°  C  for  fifteen  hours  and  allowed  to  cool  slowly  in  a 
clear  atmosphere. 

To  determine  the  porosity,  fire  shrinkage,  heat  range,  and  color, 
nine  separate  burns  were  made  using  pyrometric  cones  as  the  tempera- 
ture indicators.8 

These  burns  were  made  at  cones  010,  08,  06,  04,  03,  02,  01,  1,  2, 
and  3.  Three  briquets  of  each  shale,  oxidized  as  previously  described, 
were  placed  in  each  burn  and  the  average  measurements  of  these  taken 
as  the  data  for  plotting  the  curves.  The  firing  wras  done  under  oxi- 
dizing conditions  following  a  straight  line  time-temperature  curve. 

Burning  Shrinkage 

This  was  calculated  for  the  three  briquets  in  each  burn  on  the  dry 
length  as  basis  and  is  equal  to 

average  loss  in  length 


average  dry  length 


100. 


Porosity 

The  burned  briquets  were  weighed  dry,  immersed  in  water  for 
24  hours,  then  placed  under  water  in  vacuo  for  24  hours  (  fig.  5).  The 
saturated  weights  and  suspended  weights  were  determined  and  the 
porosities  calculated  from  the  formula 

W  —  D 


W 


x    100 


porosity 


Where  :  W  =  saturated  weight. 
D    =  dry  weight, 
S    =  weight  suspended  in  water 


TESTS  OX  SAMPLES  I  \T  GROUP  II 

Group  11  contains  83  different  samples,  including  Xos.  26  to  108. 
In  testing  so  large  a  number  it  was  obvious  from  the  experience 
gained  in  Group  I  that  it  would  be  necessary  to  save  time  and  expense 
by  devising  more  efficient  means  for  preparing  the  samples  and  mold- 
ing the  briquets. 


sOwing  to  the  erratic  behavior  of  cones,  more  consistent  results  arc  obtainable  by 
using  a  pyrometer  as  the  temperature  indicator,  and  making  all  burns  according  to  a  definite 
time-temperature  curve  after  passing  tin-  oxidation  period.  The  indicated  temperatures  in 
Centigrade  for  these  cones  are: 


Cone 

010 

OH 

06 

04 

03 

02 

01 

1 

2 

3 

Temperature  degrees 

Q50 

')<)() 

1030 

1«)70 

10<)0 

1110 

1130 

1150 

1170 

1190 

24 


CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 


A 

6-inch  wrought  iron  pipe 

B 

Cap 

C 

Machined  flange 

D 

Glass  desicator  cover 

E 

^4-inch  pipe 

F 

Outlet  pipe  with  cap 

G 

Rubber  pressure  tubing 

H 

Glass  T 

J 

Mercury  vacuum  gauge 

K 

Level  of  water 

L 

Briquets 

M 

Pipe  to  vacuum  pump 

Fig.  5.— Apparatus  for  saturating  briquets  in  vacuo. 


25 


TESTS  ON  SAMPLES  IN  GROUP  II 


Grinding  the  Samples 

The  samples  were  ground  in  a  5-foot  dry  pan  provided  with 
perforated  plates  with  one-tenth-inch  slots.  A  circular  sheet-iron  pan 
provided  with  a  slot  5  inches  wide  running  from  the  center  to  the 
circumference  was  bolted  to  the  frame  6  inches  below  the  grinding 
pan.  Heavy  brushes  were  attached  to  the  under  side  of  the  dry  pan 
and  revolved  with  it  sweeping  over  the  inner  surface  of  the  sheet- 
iron  pan.  The  dry  pan  was  set  in  motion  and  the  clay  sample  of 
approximately  45  to  50  pounds  introduced.  As  fast  as  the  material 
became  crushed  and  passed  through  the  one-tenth-inch  perforation,  it 


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Fig.  6. — a,  oxidizing  briquet  from  Group  I  showing  black  core  approaching 

the  circular  form;  h,  oxidizing  cylinder  from  Group  II. 

fell  into  the  sheet-iron  pan  and  was  swept  around  and  out  of  the  5-inch 
slot  where  it  was  collected  and  passed  through  a  ten-mesh  screen  ; 
the  tailings  thrown  back  into  the  dry  pan.  By  this  arrangement  the 
pan  became  thoroughly  and  automatically  cleaned  ready  for  the  next 
sample.  The  time  required  to  prepare  a  sample  was  approximately 
20  to  30  minutes. 


Molding  the  Briquets 
In  Group  I  the  oxidation  trials  were  made  in  the  form  of  paral- 
lelopipeds  l^"xl^j"x3/j".  Oxidation  progresses  faster  at  the 
edges  than  through  the  sides,  as  shown  in  sample  a,  figure  6.  As 
oxidation  progresses,  the  black  core  of  a  cross-section  approaches 
more  and  more  the  circular  form.  In  order  to  eliminate  the  error 
and   thereby  obtain   more  accurate   data   as   to   the    rate   of   oxidation, 


26 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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RESULTS  OF  TESTS  27 

the  oxidation  trials  in  Group  II  were  made  cylindrical  in  form,  \Y\" 
diameter  by  3j/2r'  long  (fig.  6). 

In  order  to  eliminate  the  ''personal  factor"  entering  into  hand 
molding,  as  well  as  to  introduce  the  time-saving  element,  the  oxidation 
cylinders  and  the  burning  briquets  were  molded  stiff-mud  in  a  hand 
plunger  machine  (fig.  7)  constructed  especially  for  the  purpose.  The 
machine  was  provided  with  two  interchangeable  dies — one  with  a 
cylindrical  opening  for  molding  the  oxidation  cylinders,  and  the  other 
with  an  opening  one  inch  square  for  molding  the  briquets  for  the 
burning  tests. 

The  clay  sample  tempered  with  water  to  the  proper  molding  con- 
sistency was  placed  in  the  cylinder  of  the  machine  and  a  continuous 
bar  or  column  of  the  clay  made  to  issue  by  turning  the  crank.  The 
column  passed  from  the  die  into  a  cutting  box  where  it  was  cut  into 
3^-inch  lengths  by  a  No.  26  B.  &  S.  gage  wire  bow.  The  briquets 
were  not  repressed. 

Screening  Test 

The  slaking  test  was  carried  out  the  same  as  that  described  under 
Group  I  and  the  slaked  material  passed  through  the  following  Tyler 
Standard  Screens. 


Screen 

Size 

Size 

mesh 

opening 

opening 

Inches 

Millimeters 

10 

.0650 

1.651 

20 

.0328 

.833 

35 

.0164 

.417 

65 

.0082 

.208 

100 

.0058 

.147 

150 

.0041 

.104 

Burning 

The  burning  was  done  in  the  same  manner  as  in  (iron])  I  with 
the  exception  that  two  higher  burns  were  added,  cone  4  or  1210°  C, 
and  cone  5  or  1230°  C. 

Barring  the  above  mentioned  changes,  the  remainder  of  the  work- 
was  carried  out  in  accordance  with  the  methods  described  inn  lei- 
Group  J. 

RESULTS  OF  THE  TESTS 

The  data  from  the  tests  of  the  various  samples  are  presented  at 
the  end  of  the  book  accompanied  by  curves  showing  the  burning 
behavior  of  the  clays.  For  the  sake  of  convenience  the  curves  repre- 
senting time-rate  of  oxidation,   shrinkage-temperature,   and   porosity- 


28  CLAY  MATERIALS   IN  ILLINOIS   COAL  MINES 

temperature  for  each  shale  are  plotted  on  one  sheet.  In  the  time- 
rate  oxidation  curves,  the  percentage  oxidized  areas  are  plotted  on 
the  ordinate  and  time  on  the  abscissa9.  The  porosities  and  shrinkages 
are  plotted  on  the  ordinate  and  the  temperatures,  expressed  on  cones, 
on  the  abscissa.  The  porosity  scale  is  indicated  at  the  left  and  the 
shrinkage  scale  (twice  the  magnitude  of  the  porosity  scale)  at  the  right 
of  the  diagram. 

Where  several  samples  have  been  taken  from  the  same  mine 
or  from  adjacent  points  and  curves  have  been  plotted  on  the  same 
sheet  as  far  as  possible.  As  a  matter  of  convenience  for  reference 
and  comparison  of  clays  from  the  same  general  locality,  the  data 
sheets  and  curves  have  been  arranged  in  groups  corresponding  to  the 
various  coal  districts  of  the  State  (fig.  8).  Within  these  districts  the 
samples  have  been  further  arranged  alphabetically  by  counties  and  by 
towns. 

Afore  or  less  similarity  may  be  noted  in  the  characteristics  of  the 
roof  shales  from  a  given  district,  especially  in  regard  to  their  burning 
behavior.  The  plastic  properties  and  the  general  molding  and  drying 
behavior  of  the  materials  seem  to  be  determined  largely  by  the  local 
conditions  during  or  subsequent  to  their  deposition.  The  constitution, 
as  evidenced  by  the  fluxing  action  during  burning  and  the  porosity- 
temperature  relation  seems  to  be  quite  similar  in  samples  over  a  large 
area.  The  properties  of  the  floor  materials  show  much  greater  varia- 
tion even  within  relatively  small  areas. 

District  No.  I. — Samples  were  taken  from  mines  at  Coal  City, 
Wilmington,  Seneca,  La  Salle,  Black  Hollow,  Oglesby,  Wenona. 
Cherry,  Spring  Valley,  Minonk,  and  Sparland.  W^ith  the  exception 
of  the  samples  from  Wenona  the  roof  shales  of  the  district  show 
considerable  similarity  in  their  burning  behavior.  They  vitrify  at 
comparatively  low  temperatures,  show  a  short  heat  range  in  burning, 
and  overburn  easily.  As  has  been  shown  these  characteristics  elim- 
inate them  as  possibilities  for  the  manufacture  of  vitrified  wares  such 
as  paving  brick.  They  may  be  used  for  more  or  less  porous  products 
such  as  common  brick,  front  brick,  and  hollow  ware  in  case  the  mold- 
ing and  drying  properties  are  satisfactory.  Common  brick  requires 
sufficient  degree  of  plasticity  to  permit  molding  by  the  stiff-mud 
process.  For  hollow  ware  the  same  qualification  may  be  made,  but 
the  plasticity  must  be  greater  than  for  brick,  and  a  greater  strength 
is  required  in  the  dried  body.  For  front  brick  there  must  be,  in  addi- 
tion  to  satisfactory  molding  and  drying  behavior,   a  desirable   color. 


9Purdy,  R.  C.  and  Moore,  J.  K.,  Pyro-physical  and  chemical  behavior  of  clays:  Trans. 
Am.   Cer.   Soc.  vol.  9,  p.   211,   1907. 


Fig.  8.— Map  showing  division  of  State  into  districts  and  location  of  sam- 
ples tested. 

(29) 


30  CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 

The  color  is  determined  largely  by  the  presence  or  absence  of  soluble 
salts,  such  as  sulphates,  and  depends  entirely  on  the  local  conditions 
of  the  deposit. 

District  No.  3. — Only  one  sample  of  roof  material  was  taken 
from  this  district.  Floor  materials  from  Coal  Valley,  Matherville 
and  Colchester  were  quite  sandy  and  very  different  in  character  from 
the  well-known  Colchester  clay  in  McDonough  County. 

District  No.  4. — Samples  were  obtained  from  Peoria,  South  Bar- 
tonville,  Bloomington,  Athens,  Decatur,  Niantic,  Cantrall,  Selbytown, 
Sherman,  and  Springfield.  Few  of  the  materials  from  the  district  are 
suitable  for  manufacturing  purposes.  Nearly  all  the  floor  materials 
contain  considerable  amounts  of  bituminous  matter  and  give  great 
trouble  in  oxidation.  Most  of  the  clays  crack  in  burning,  have  a 
very  short  heat  range,  and  overburn  easily. 

District  No.  5. — Only  two  samples  were  tested,  a  roof  shale  and 
a  floor  clay  from  the  mine  of  Saline  County  Coal  Company  at  Harris- 
burg. 

District  No.  6. — Samples  of  floor  materials  from  Sesser,  Rend, 
Herrin,  and  Marion,  and  a  roof  material  from  Rend  were  tested.  Of 
these,  the  floor  material  from  Sesser  and  the  roof  shale  at  Rend  are 
the  only  suitable  clays  for  manufacturing  purposes. 

District  No.  7. — Samples  of  floor  material  were  taken  at  Panama, 
Auburn,  Mascoutah,  Belleville,  Freeburg,  and  O'Fallon,  and  two  sam- 
ples of  roof  materials  at  Duquoin.  The  floor  clays  in  the  district,  as 
represented  in  these  tests,  overburn  readily  before  reaching  vitrification. 
Most  of  the  samples  were  unsuitable  for  manufacturing  purposes, 
due  to  their  short  heat  range  and  tendency  to  crack  in  burning.  The 
roof  shale  from  Duquoin  and  the  floor  clay  from  Auburn  are  promis- 
ing clays  for  manufacturing  purposes. 

ILLINOIS  ROOF  SHALES  AND  FLOOR  CLAYS 
The   following   notes   concerning   floor   clays   and   roof    shales    in 
Illinois  coal  mines  were  tabulated   for  a  recent  Survey  publication10 
and  are  reprinted  here  as  a  convenient  reference  to  general  roof  and 
floor  characteristics  in  the  various  districts. 


inYoung,    L.    E.,    Surface    subsidence    in    Illinois    resulting    from    coal    mining:     Illinois 
Coal  Mining  Investigations  Bull.    17,  p.  24,  1916. 


ILLINOIS  ROOF  SHALES  AND  FLOOR  CLAYS 


31 


Character  of  roof  and  floor  of  the  commercial  coal  beds  throughout  Illinois 

District  I 


Coal  bed 


No.  2 


No.  5 


No.  7 


Roof 


Floor 


Gray  shale,  replaced  in  places 
by  a  black  shale  about  3  feet 
thick. 


Varies  from  a  gray  shale  to 
black  "slate",  sandstone  and  lo- 
cally limestone ;  "white  top" 
roof  in  certain  areas. 

Gray  silicious  shale  35  or  more 
feet  thick.  Immediate  roof  is 
generally  darker  than  the  upper 
beds  of  shale. 


Dark-gray  lire  clay  up  to  sev- 
eral feet  thick.  In  some  parts 
of  the  La  Salle  field  a  hard 
sandstone  lies  directly  beneath 
the  coal. 

Gray  fire  clay  1  to  4  feet  thick, 
underlain  by  sandstone  or 
sandy  shale. 

Gray  fire  clay  2  to  3  feet  thick 
lying  on  sandstone.  Black  shale 
in  places  forms  the  floor. 


District  III 


No.  1 


No.  2 


In  Mercer  and  Rock  Island 
counties,  hard  black  shale  2  to 
5  inches  thick ;  limestone  cap 
rock,    1   to  4   feet. 


Hard  black  shale  generally  not 
over  1  foot  thick,  overlain  by 
a  limestone  cap  rock  3  feet 
thick. 


Light  gray  micaceous  fire  clay 
which  heaves  badly  when  wet. 
In  places  an  irregular  band  (3 
to  6  inches)  of  carbonaceous 
shale  or  sandstone  lies  imme- 
diately below   the  coal. 

Gray  fire  clay  containing  nod- 
ules of  iron  pyrites. 


No.  5 


No.  5 


District  IV 


Black  sheety  shale  up  to  35 
feet  thick.  A  limestone  cap 
rock  over  the  shale.  Where 
shale  is  thin,  the  cap  rock  be- 
comes the  roof. 


( i ray  fire  clay. 


District  V 


Light  gray  to  black  shale,  in 
some  areas  laminated  with  coal 
for  a  distance  of  3  feet  above 
seam.  Shale  of  immediate  roof 
is  weak. 


Fire  clay  generally.  In  some 
areas  the  clay  is  sandy  and 
heaves  badly  when  wet. 


32 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


Character  of  roof  and  floor  of  the  commercial  coal  beds  throughout  Illinois 

(Concluded) 
District  VI 


Coal  Bed 

Roof 

Floor 

No.  6  in : 

Coal  is  left  as  immediate  roof. 

Gray  fire  clay  2  to  8  feet  thick 

Franklin 

Upon  the  coal  is  a  thin  bed  of 

underlain  by  a  sandy  limestone. 

draw  slate,  and  within  25  feet 

Heaves  in  only  a  few  mines. 

above  the  coal  is  usually  a  lime- 

stone   cap    rock    4    to    10    feet 

thick. 

Williamson 

Coal  is  left  generally  as  roof. 

Gray  fire  clay  2  to  4  feet  thick 

Tn  a  number  of  mines  the  lime- 

underlain   by    limestone.      The 

stone   cap   rock   is    missing   or 

floor   heaves    badly   in    several 

higher  than  in  Franklin  County. 

mines. 

District  VII 


No.  6  in : 

Limestone    cap    rock,    5    to    15 

Clay,  18  inches  to  8  feet  in  most 

Clinton 

feet    thick.      In    places    black 
shale    between    limestone    and 
coal. 

places  on  shale. 

Christian 

Black   shale   overlain   by   lime- 
stone ranging  from  1  to  20  feet. 
In   some   mines   shale  between 
coal  and  limestone. 

Clay  of  variable  thickness. 

Macoupin 

Black  shale  with  limestone  cap 

Clay  averaging  about    1    foot. 

rock. 

Beneath  the  clay  there  is  gen- 
erally limestone. 

Gray  or  black  shale  of  varying 

Madison 

thickness  overlain  by  limestone 
ranging    in    thickness    from    a 
few  feet  to  as  much  as  30  feet. 
In  some  places  limestone  rests 
on  the  coal. 

Limestone   cap   rock,   about   15 

Marion 

feet  thick. 
Limestone  cap  rock. 

Clay  of  varying  thickness. 

Montgomery 

Black  shale  and  limestone. 

Clay  of   variable  thickness. 

St.  Clair 

Black  shale  under  limestone  to 

Thin  clay  on  limestone. 

Perry, 

the  west  of  Duquoin  anticline. 

Clay  of  variable  thickness. 

Randolph,  and 

To    the    east,    the    same    lime- 

Washington 

stone,  if  present  at  all,"  is  100 
feet  above  coal. 

Shelby  and 

Shale  and  limestone. 

Shale,  clay,  limestone. 

Moultrie 

Sangamon 

Irregular   shale   and  limestone. 

Thin  clay. 

"Cady,    G.    H.,    Coal   resources   of    District   VI: 
series    Bull.    15,    1916. 


111.    State    Geol.    Survey    Coal    Mining 


RESULTS  OF  LABORATORY  TESTS  OF  SAMPLES 

In  the  following  pages,  each  sample  is  described,  and  the  results 
of  burning  tests  are  shown  by  means  of  diagrams.  For  a  complete 
list  of  mines  from  which  samples  were  taken,  the  reader  should  refer 
to  the  table  on  pages  34  and  35. 


(23) 


34 


CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  37 


BARR  BRICK  COMPANY,  STREATOR 

(See  figure  9) 
Sample  25. — Dark,  slate-gray  shale  of  medium  hardness;  contains  gypsum, 
sample  comparatively  free  from  carbonaceous  matter  and  concretions. 

No  slaking  and  screening  tests  made. 

Plasticity    Fair 

Molding   properties Good 

Drying  properties   Good 

Linear  drying   shrinkage 4  71% 

Volume  drying  shrinkage 15.77% 

Tempering  water   22.17% 

Oxidation  Complete  in  1  hour. 

Maximum  safe  burning  temperature Above  cone  3. 

Heat  range. .  .Temperature  not  carried  high  enough  to  determine  this. 

When  burned  at  cone  3 — 

Burning  shrinkage   6.82% 

Total   shrinkage    11.53% 

Porosity     13.70% 

Fracture     Stony 

Color  Dark  red ;  scums  badly. 

Possibilities Common,  front,  and  paving  brick,  hollow  ware. 

Precautions    For  front  brick  barium    salt   should  be 

added  to  overcome  scumming. 

BURLINGTON  PAVING  BRICK  COMPANY,  GALESBURG 
(See  figure  9) 
Sample  24. — Blue-gray    shale,    somewhat    sandy,    shows   a   trace   of   calcium 
sulphate,  otherwise  sample  seems  to  be  quite  uniform. 
No  slaking  or  screening  tests  made. 

Plasticity    Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying   shrinkage 5.54'  . 

Tempering  water    23.97% 

Oxidation  Complete  in  1  hour. 

Maximum  safe  burning  temperature Above  cone  3. 

Heat  range   Cone  3  to  possibly  cone  6. 

When  burned  at  cone  3 — 

Burning  shrinkage   8.77% 

Total    shrinkage    .  .  .• 14.31%. 

Porosity     7.99% 

Fracture  Dull,  smooth,  stony. 

Color Dark  red,  scums. 

Possiblities  Common,  front,  and  paving  brick,  hollow  ware. 


38  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


ILLINOIS  CLAY  COMPANY,  OGLESBY 
(See  figure  10) 
Coal  bed— No.  2. 

Sample  26. — Represents  roof  material  up  to  10  feet  above  coal  at  the  out- 
crop along  Vermilion  River;  medium  hard,  light-gray  shale  containing  brown 
iron  streaks,  hard  clay  concretions  stained  with  iron  oxide  and  a  small  amount 
of  carbonaceous  matter. 

Slaking  test Slakes  imperfectly. 

No  screening  tests  made. 

Plasticity Fair 

Molding  properties    Good 

Drying  properties  Good 

Linear  drying  shrinkage 7.33% 

Volume  drying  shrinkage 25.40% 

Tempering  water   33.40% 

Oxidation  Complete  in  5  hours. 

Maximum  safe  burning  temperature Cone  04- 

Heat  range  Cone  05  to  cone  04 ;  bloats  above  cone  04. 

When  burned  at  cone  04 — 

Burning  shrinkage   9.80% 

Total    shrinkage    7.13% 

Porosity     0.38% 

Fracture    Vitreous 

Color Dark  cherry  red ;  free  from  scum. 

Possibilities Common  and  building  brick,  hollow  ware. 

Precautions    Shale     has     comparatively     short     heat 

range    and    is    sensitive    to    bloating 

when     overfired,     hence     should     be 

burned  at  a  safe  limit  below  cone  03. 

Sample  53. — Represents  roof  material   from  6  to   16  feet  above  outcrop  of 

coal  along  Vermilion  River;  impurities,  sand  and  sulphur  balls;  shale  somewhat 

weathered  in  appearance ;  contains  brown  ironstones  and  iron  oxide  apparently 

from  decomposed  pyrite. 

Slaking  test  Slakes  very  little. 

Residues  left  on  screens — 

10  mesh   92.50% 

20  mesh   1.24% 

35  mesh   1.40% 

65  mesh   1.74% 

100  mesh  0.73% 

150  mesh 0.31% 

Passed  150  mesh 2.08% 

Plasticity   Fair 

Molding  properties    Good 

Drying  properties  Good 

Linear  drying  shrinkage 5.75% 

Volume  drying  shrinkage 16.56% 

Tempering  water   28.20% 

Oxidation  Complete  when  first  trial  was  drawn. 

Maximum  safe  burning  temperature Cone  04- 

Heat  range   Short ;  bloating  begins  above  cone  04. 


LABORATORY  TESTS 


39 


When  burned  at  cone  04 — 

Burning  shrinkage   , 8.47% 

Total    shrinkage    14.22% 

Porosity     0.42% 

Fracture    Vitreous 

Color Cherry  red  ;   scums. 

Possibilities Common  brick  and  hollow  ware. 


Precautions 


Burning  should  be  done  at  a  safe  tem- 
perature below  that  at  which  bloating 
begins. 


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ST.   PAUL  COAT.  COMPANY,   MINE   NO.  2,  CHERRY 
(  Sec  figure  1 1 ) 
Coal  bed — No.  2. 

Sample  21. — Represents  roof  material  above  coal  ;  sample  consists  of  a  mix- 
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Slaking  test  Slakes  slowly  and  incompletely. 

Residues  left  on  screens — 

10  mesh    29.50'  , 

20  mesh   12.3095 

60  mesh   7.20% 

100  mesh   4.50% 

120  mesh   0.48% 

Passed  120  mesh 46.02% 


40 


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LABORATORY  TESTS  41 

Plasticity   Fair 

Molding  properties    Good 

Drying  properties   Good 

Linear  drying   shrinkage 5.58% 

Tempering  water  25.78% 

Oxidation  Difficult,  73%  oxidized  in  9  hours. 

Maximum  safe  burning  temperature Cone  2 

Heat  range Short ;  bloats  at  cone  3  ;  cracks  in  burning. 

When  burned  at  cone  2 — 

Burning  shrinkage   8.37% 

Total   shrinkage    13.95% 

Porosity     3.07% 

Fracture    Vitreous 

Color   Dark  red ;  scums. 

Possibilities  An  impracticable  material,  as  it  is  diffi- 
cult to  oxidize,  has  short  heat  range, 
and  cracks  in  burning. 


SPRING  VALLEY  COAL  COMPANY,  MINE  NO.  5,  DALZELL 
(See  figures  12  and  13) 
Depth  of  shaft— 413  feet. 

Area  mined — 54  acres ;  less  than  50  per  cent  is  underlain  by  clay,  in  east 
part  of  mine  sandstone  lies  below  the  coal. 
Coal  bed— No.  2. 

Thickness  of  roof — Reported  20  feet  at  shaft. 

Sample  62. — Location  in  mine,  straight  W.  2d  R.  1st  L. ;  sample  represents 
roof  material  from  0  to  42  inches  above  coal ;  slate-gray  shale  containing  brown 
spots  that  show  a  weak  effervescence  with  hydrochloric  acid  and  a  reaction  for 
iron;  contains  small  amount  of  calcium  sulphate;  shows  occasional  slickensides. 

Slaking  test   Incomplete  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   78.40% 

20  mesh    6.98% 

35   mesh    5.12% 

65  mesh   3.80% 

100  mesh   1.28% 

150  mesh   0.63% 

Passed  150  mesh 2.79% 

Plasticity   Fair 

Molding   properties    Good 

Drying  properties    Tendency  to  warp. 

Linear  drying  shrinkage    4.20% 

Volume  drying  shrinkage    13.80% 

Tempering  water   22.20% 

Oxidation  Complete  in  7  hours. 

Maximum  safe  burning  temperature Cone  04 

Heat  range Short ;  occasional  surface  pitting  occurs. 

When  burned  at  cone  04 — 

Burning  shrinkage   7.61% 

Total   shrinkage    11.81% 

Porosity     2.04% 

Fracture    Vitreous 

Color  Medium  dark  red  ;  scums  excessively. 

Possibilities    Common  brick. 


42  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Sample  72. — Location  in  mine,  N.  6th  R.,  one-half  mile  from  shaft;  sample 
represents  roof  material  up  to  5  feet  above  coal;  medium  hard,  gray  shale,  with 
hard  brown  patches ;  contains  numerous  pyrite  granules,  calcium  sulphate,  and 
iron  carbonate. 

Residues  left  on  screens — 

10  mesh   70.95% 

20  mesh   70.41% 

35  mesh   8.21% 

65  mesh   6.16% 

100  mesh   2.58% 

150  mesh   1.02% 

Passed  150  mesh  0.69% 

Plasticity   Fair 

Molding  qualities Good 

Drying  properties  Good 

Linear  drying  shrinkage 4.23% 

Volume  drying  shrinkage   13.40% 

Tempering  water   23.04% 

Oxidation    Complete  in  8  hours. 

Maximum  safe  burning  temperature Cone  04 

Heat  range Cone  06  to  cone  04 ;  bloats  above  cone 

04 ;  surface  pits  a  little. 
When  burned  at  cone  04 — 

Burning  shrinkage   8.26% 

Total   shrinkage    12.49% 

Porosity     0.70% 

Fracture    Vitreous 

Color  Light  cherry  red ;  scums. 

Possibilities   Common  and  front  brick,  hollow  ware. 

Sample  3Q. — Location  in  mine,  straight  W.  2d  S.,  1st  left;  sample  represents 
floor  material  from  0  to  14  inches  below  coal ;  structure  resembles  that  of  fire 
clay ;  medium  hard,  light-gray  clay,  stained  brown  in  spots ;  contains  carbon- 
aceous matter  as  plant  fossils,  granules  of  iron  carbonate,  and  small  calcium 
carbonate  concretions. 

Slaking  test Slakes  in  39  hours. 

Residues  left  on  screens — 

10  mesh   4.07% 

20  mesh   1.95% 

35  mesh   5.21% 

65  mesh 7.22% 

100  mesh   6.42% 

150  mesh   2.52% 

Passed  150  mesh 72.61% 

Plasticity   Good 

Molding  properties    Good 

Drying  properties  Good 

Linear  drying  shrinkage    5.81% 

Tempering  water   19.60% 

Oxidation  Complete  in  13  hours. 

Maximum  safe  burning  temperature Cone  2 

Heat  range  Good,   cone   04  to   cone   2.     Occasional 

surface  pits  occur.    Bloats  above  cone 
2. 


LABORATORY  TESTS  43 

When  burned  at  cone  2 — 

Burning  shrinkage   4.57% 

Total   shrinkage    10.38% 

Porosity    9.47% 

Fracture     Stony 

Color    Light   salmon   at   cone   010,   changes  to 

light   brown   at    cone   04;    color   does 
not  change  above  this  temperature. 

Possibilities   Common  and  face  brick,  hollow  ware. 

Precautions Would  require  considerable  care  during  oxidation. 

Sample  40. — Same  location  as  Sample  39 ;  sample  represents  floor  material 
from  14  to  24  inches  below  coal ;  similar  in  appearance  to  Sample  39. 

Slaking  test Slakes  slowly  and  imperfectly. 

Residues  left  on  screen — 

10  mesh  7.60% 

20  mesh  6.54% 

35  mesh  13.70% 

65  mesh   11.05% 

100  mesh   8.45% 

150  mesh  3.75% 

Passed  150  mesh 48.97% 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage 5.82% 

Tempering  water   19.60% 

Oxidation  Difficult,  93%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  1 

Heat  range  Cone  04  to  cone  1.     Occasional  surface 

pits    occur.       Bloating    occurs    above 
cone  1. 
When  burned  at  cone  1 — 

Burning  shrinkage   5.60% 

Total   shrinkage    1 1.42% 

Porosity     7.33% 

Fracture     Stony 

Color    Salmon  at  cone  010,  changes  to  brown 

at   cone   04.      Color   does   not    change 
above  this  temperature. 

Possibilities   Common  and  front  brick,  hollow  ware. 

Precautions    Would  require  careful  oxidizing. 

Sample  63. — Location  in  mine,  straight  W.  2d  R.  1st  L. ;  sample  represents 
floor  material  below  coal ;  a  mixture  of  light-gray  with  dark,  almost  black,  clay 
stained  brown  in  spots;  shows  occasional  sickensides ;  contains  considerable  car- 
bon as  plant  fossils. 

Slaking  test Slaked  in  11  hours  to  a  plastic  mass. 

Residues  left  on  screens — 

10  mesh   0.07% 

20  mesh   0.04% 

35  mesh   0.11% 

65  mesh   0.26% 

100  mesh   0.23% 

150  mesh   0.35% 

Passed  150  mesh  98.94% 

Plasticity   Good 

Molding  properties  Good 


44  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Drying  properties  Warps  in  drying 

Linear  drying  shrinkage 10.28% 

Tempering  water   31.00% 

Oxidation  Difficult,  56%  oxidized  in  14  hours. 

Maximum   safe  burning  temperature Cone  06 

Heat  range Very  short;  bloats  above  cone  06;  cracks  in  burning. 

When  burned  at  cone  06 — 

Burning  shrinkage   5  34% 

Total   shrinkage    15.62% 

Porosity     7.08% 

Fracture Dense,  stony. 

Color    Light    salmon   at   cone   010,   changes   to 

light  brown  at  cone  08. 
Possibilities  Very  unsuitable  material,  as  it  has  high- 
drying  shrinkage  and  warps,  is  diffi- 
cult to  oxidize,  has  short  heat  range, 
cracks  in  burning,  and  is  sensitive  to 
overfiring  as  indicated  by  bloating. 

MARQUETTE  THIRD  VEIN  COAL  COMPANY,  MARQUETTE  MINE,  MARQUETTE 

(See  figure  14) 
Depth  of  shaft— 282  feet. 
Coal  bed— No.  2. 

Sample  II. — Sent  by  company;  represents  roof  of  coal;  medium  hard,  gray 
shale;  contains  carbonaceous  material,  granular  concretions  of  partly  decom- 
posed pyrite,  and  calcium  sulphate. 

Slaking  test  Slakes  slowly  and  incompletely. 

Residues  left  on  screens — 

10  mesh   48.50% 

20  mesh   6.70% 

60  mesh   8.00% 

100  mesh   0.65% 

120  mesh   0.93% 

Passed  120  mesh 35.22% 

Plasticity Fair 

Molding  properties  Good 

Drying  properties  Good 

Linear  drying  shrinkage 6.44% 

Volume  drying  shrinkage    20.30% 

Tempering  water   26  80% 

Oxidation  Difficult,  92%  oxidized  in  8  hours. 

Maximum   safe  burning  temperature Cone  02 

Heat  range Short ;  cracks  in  burning  ;  bloats  above  cone  02. 

When  burned  at  cone  02 — 

Burning  shrinkage   9.25% 

Total    shrinkage    15.69% 

Porosity 8.29% 

Fracture    Vitreous 

Color Red,  scums  considerably. 

Possibilities    A  troublesome  material,  as  it  is  difficult 

to    oxidize,     cracks    in    burning,    has 
short  heat  range,  is  sensitive  to  over- 
burning,  and  scums  excessively. 
Sample  14. — Sent    by    company;    represents    floor    of    coal;    medium    hard, 
light-gray  shale ;   contains  calcium  sulphate   and  carbonaceous  matter  as  plant 
fossils. 

Slaking  test Slakes  slowly. 


LABORATORY  TESTS  45 

Residues  left  on  screens — 

10  mesh   0.00% 

20  mesh  , 0.10% 

60  mesh   0.10% 

100  mesh    0.10% 

120  mesh 0.00% 

Passed  120  mesh 99.70% 

Plasticity        High 

Molding   properties    Good 


1         |       No.   11        |        I 
Time-rate  oxidation  at  650°C. 

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Fig.  14. — Graphic  illustration  of  the  laboratory  tests  of  Sample  11,  roof 
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Vein  Coal  Company,  Marquette. 


Drying  properties  Good 

Linear  drying  shrinkage 6.66% 

Volume  drying  shrinkage   22.59% 

Tempering  water   23.587c 

Oxidation  Difficult,  89%  oxidized  in  9  hours. 

Maximum   safe  burning  temperature Cone  3 

Heat  range Cone  02  to  cone  3,  cracks  in  burning. 

When  burned  at  cone  3 — 

Burning  shrinkage   7.48% 

Total   shrinkage    14.14% 

Porosity     174% 

Fracture     Stony 

Color   Dark,  dull  red  ;  scums. 

Possibilities    A  very  unsuitable  material,  as  it  is  dif- 
ficult to  oxidize  and  cracks  in  burning. 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  47 


BIG  FOUR  WILMINGTON  COAL  CO.,  MINE  NO.  6,  COAL  CITY 
(See  figures  15  and  16) 
Depth  of  shaft— 95  feet. 
Area  mined — 200  acres. 
Coal  bed— No.  2. 

Thickness  of  roof — Reported  to  be  35  feet  like  samples. 

Sample  41. — Location  in  mine,  S.  entry,  2,700  feet  from  shaft ;  sample  rep- 
resents roof  material  above  coal;  medium  soft  gray  roof  shale,  somewhat  sandy; 
contains  numerous  well-defined  plant  fossils  and  occasional  granules  of  lime- 
iron  carbonate. 

Slaking  test.  .Very  little  affected,  broke  up  into  a  few  large  fragments. 
Residues  left  on  screens.  .Practically  all  remained  on  10-mesh  screen. 

Plasticity     Low 

Molding  properties Tears  at  the  corners  of  the  die. 

Drying  properties   Good 

Linear  drying  shrinkage 3.43% 

Tempering  water   20.70% 

Oxidation   Complete  in  9  hours. 

Maximum  safe  burning  temperature Cone  1 

Heat  range  Cone  04  to  cone   1 ;   occasional   surface 

pits  occur;  bloats  above  cone  1. 
When  burned  at  cone  1 — 

Burning  shrinkage   7.98% 

Total  shrinkage 11.41% 

Porosity    8.79% 

Fracture    Dense,    stony. 

Color  Cherry  red  ;  free  from  scum. 

Possibilities    Common  and   front  brick. 

Precautions  Clay  is  somewhat  short  and  would  re- 
quire fine  grinding  and  thorough  tem- 
pering to  work  without  trouble  in  the 
die. 

Sample  46. — Location  in  mine,  NE.  entry  1,500  feet  from  shaft;  sample  rep- 
resents roof  material  above  coal;  medium  soft,  gray,  somewhat  sandy,  mica- 
ceous shale  ;  otherwise  very  uniform  in  appearance. 

Slaking  test    No  effect  noticeable 

Residues  left  on  screens — Practically  all   residue  remains  on   10-mesh 
screen. 

Plasticity    Fair 

Molding   properties    Fair 

Drying  properties Good 

Linear  drying  shrinkage 2.S4' < 

Tempering  water    19.65% 

Oxidation  Complete  in  1  hour. 

Maximum  safe  burning  temperature  Cone  1 

Heat  range   Good,  cone  04  to  cone  1 

When  burned  at  cone  1 — 

Burning  shrinkage   9.62% 

Total    shrinkage    12.46% 

Porosity     2.83% 

Fracture  Dull,  dense,  uniform. 

Color  Dark  red  ;  comparatively  free  from  scum. 

Possibilities    Common  and   front  brick. 


48  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Sample  60. — Location  in  mine,  in  entry  200  feet  east  of  shaft ;  sample  rep- 
resents 7  feet  of  floor  material ;  medium  hard,  light-gray  clay  of  fine  sandy 
character;  apparently  free  from  carbonaceous  matter,  pyrite,  carbonates,  and 
sulphates. 

Slaking  test  Partially  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   54.00% 

20  mesh 0.54% 

35  mesh   0.54% 

65  mesh   2.41% 

100  mesh   0.39% 

150  mesh   0.23% 

Passed   150  mesh    41.89% 

Plasticity   Good 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    4.28% 

Tempering  water   20.00% 

Oxidation  Complete  when  first  trial  was  drawn. 

Maximum  safe  burning  temperature Cone  1 

Heat  range Cone  03  to  cone  1 ;  bloats  above  cone  1. 

When  burned  at  cone  1 — 

Burning  shrinkage   7.21  % 

Total  shrinkage 11.49% 

Porosity 5.77% 

Fracture   Fine  grained,  stony. 

Color   Dark  dull  red. 

Possibilities Common  and  front  brick,  hollow  ware. 

Sample  61. — Location  in  mine,  in  pump  room ;  sample  represents  2  feet  of 
floor  material ;  soft,  weathered,  light-gray  shale  stained  yellow  to  brown  in 
spots ;  contains  some  carbonaceous  matter  and  occasional  pyrite  concretions. 

Slaking  test   Slakes  in  13  hours. 

Residues  left  on  screens — 

10  mesh   9.82% 

20  mesh   0.25% 

35  mesh 1.15% 

65  mesh   2.05% 

100  mesh   1.75% 

150  mesh   , 0.84% 

Passed  150  mesh  93.14% 

Plasticity Good 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage 5.71% 

Tempering  water 24.30% 

Oxidation  Complete  in  9  hours. 

Maximum  safe  burning  temperature Cone  1 

Heat  range Cone  04  to  cone  1. 

When  burned  at  cone  1 — 

Burning  shrinkage   8.03% 

Total   shrinkage    13.74% 

Porosity     2.00% 

Fracture    Vitreous 

Color Medium  dull  red ;  scums  a  little. 

Possibilities Common  and  front  brick,  hollow  ware. 


LABORATORY  TESTS  49 

Sample  106. — Location  in  mine,  face  2,700  feet  south  of  shaft;  sample  rep- 
resents floor  material  immediately  below  coal ;  medium  hard,  light  to  dark-gray 
clay ;  structure  resembles  that  of  fire  clay ;  shows  slickensides ;  contains  carbon- 
aceous matter  as  plant  fossils  and  calcium  sulphate. 

Slaking  test Slakes  in  11  hours. 

Residues  left  on  screens — 

10  mesh    0.10% 

20  mesh   0.70% 

35  mesh 3.65% 

65  mesh   4.74% 

100  mesh    2.99% 

150  mesh   1.39% 

Passed  150  mesh 86.43% 

Plasticity    Good 

Molding   properties    Good 

Drying  properties Slight  tendency  to  warp ;  scums. 

Linear  drying  shrinkage 5.95% 

Tempering  water   23.40% 

Oxidation  Complete  in  8  hours. 

Maximum  safe  burning  temperature Cone  01 

Heat  range Cone  04  to  cone  01 ;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage  7.79% 

Total  shrinkage    13.74% 

Porosity    1.07  % 

Fracture    Vitreous 

Color   Very  light  red  ;  scums  badly. 

Possiblities   Common  brick,  hollow  ware. 

Precautions    To   reduce   shrinkage   and   to   overcome 

warping,     sand     or    grog     should     be 
added  to  the  clay. 


CHICAGO,  WILMINGTON   &   VERMILION  COAL  CO.,   MINE  NO.   1,   SOUTH 

WILMINGTON 

(See  figures  17  and  18) 
Depth  of  shaft— 190  feet. 
Area  mined — 640  acres. 
Coal  bed— No.  2. 

Thickness  of  roof — Reported  35  feet  of  material  at  shaft  like  samples. 
Thickness  of  floor — 30  inches  at  pump  room. 
Impurities   in   roof — Few   sulphur  balls,   some   sand. 

Sample  55. — Represents  roof  material  up  to  3  feet  above  coal;  medium 
hard,  dark-gray  shale,  apparently  free  from  carbon,  pyrite,  and  carbonates ; 
contains  occasional  hard  clay  concretions  streaked  with  brown. 

Slaking  test  Slakes  imperfectly. 

Residues  left  on  screens — 

10  mesh   84.50% 

20  mesh   4.55% 

35  mesh  3.457" 

65  mesh   1.71% 

100  mesh    0.66% 

150  mesh   0.29% 

Passed  150  mesh  4.84% 

Plasticity    Fair 

Molding  properties Fair 


50 


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LABORATORY  TESTS  51 

Drying  properties   Good 

Linear  drying  shrinkage    4.05% 

Volume  drying  shrinkage   11.14% 

Tempering  water   20.30% 

Oxidation Complete  in  1  hour. 

Maximum  safe  burning  temperature Cone  04 

Heat  range Very  short ;  begins  to  bloat  above  cone  04. 

When  burned  at  cone  04 — 

Burning  shrinkage   8.18% 

Total  shrinkage 12.23% 

Porosity     0.41% 

Fracture    Vitreous 

Color Dark  cherry  red  ;  comparatively  free  from  scum. 

Possibilities  Common  and  front  brick,  hollow  ware. 

Precautions  Because  of  short  heat  range  the  prod- 
ucts out  of  kiln  would  vary  consid- 
erably in  color,  size,  and  porosity. 

Sample  67. — Location  in  mine,  on  SE.  entry;  sample  represents  roof  material 
up  to  6  feet  above  coal ;  hard,  light-gray  roof  shale  of  fine  sandy  structure,  com- 
paratively uniform  and  free  from  deleterious  matter. 

Slaking  test Very  little  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   93.29% 

20  mesh   1.26% 

35  mesh   0.87% 

65  mesh 0.72% 

100  mesh   0.42% 

150  mesh   0.26% 

Passed  150  mesh  3.18% 

Plasticity   Fair 

Molding  properties Fair 

Drying  properties  Good 

Linear  drying  shrinkage  2.76% 

Volume  drying  shrinkage 8.78% 

Tempering  water    19.80% 

Oxidation Completely  oxidized  when  first  trial  was  drawn. 

Maximum  safe  burning  temperature Cone  01 

Heat  range Cone  04  to  cone  01  ;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage   9.35%- 

Total  shrinkage 12.11%; 

Porosity     5.50% 

Fracture    Dense,   stony. 

Color Dark,  cherry  red  ;  very  slightly  scummed. 

Possibilities  Common  and  front  brick. 

Sample  27. — Location  in  mine,  face  SE.  entry ;  sample  represents  floor  clay 
4  to  13  inches  below  coal,  the  first  4  inches  immediately  below  coal  was  a  car- 
bonaceous clay;  hard,  bine-gray  clay  with  structure  resembling  that  of  fire  clay; 
contains  considerable  bituminous  matter  in  thin  seams  and  streaks  and  nodules 
of  pyrite. 

Slaking  test Slakes  slowly  and  imperfectly. 

Residues  left  on  screens — 

10  mesh   45.38% 

20  mesh    1 1.92% 

35  mesh   12.84% 

65  mesh   12.31% 

100  mesh    4.47% 

150  mesh    1.91% 

Passed  150  mesh   ,, i]\}?(/' 


52  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Plasticity   Good 

Molding  properties Good 

Drying  properties  Good 

Linear  drying  shrinkage 5.86% 

Volume  drying  shrinkage 18.40% 

Tempering  water    22.50% 

Oxidation Difficult,  92%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  5 

Heat  range Cone  1  to  cone  5,  very  sensitive  to  flash- 
ing;   high    porosity    of    trials   due    to 
burning    out    of    carbon.     Tends    to 
bloat  above  cone  5. 
When  burned  at  cone  5 — 

Burning  shrinkage   6.91  % 

Total   shrinkage 12.77% 

Porosity     17.86% 

Fracture     Stony 

Color Dark  buff  at  cone  010,  grayish  buff  at  cone  5. 

Possibilities Common  and  front  brick ;  fireproofing. 

Precautions     Clay  would  require  careful  burning  dur- 
ing oxidation  period. 

Sample  28. — Same  location  in  mine  as  Sample  27 ;  sample  represents  floor 
clay  from  13  to  27  inches  below  coal ;  structure  characteristically  that  of  a  fire 
clay ;  shows  well-developed  slickensides ;  contains  gypsum,  carbonaceous  matter, 
as  plant  fossils,  and  nodules  of  partly  decomposed  pyrite. 

Slaking  test Slakes  in  15  hours. 

Residues  left  on  screens — 

10  mesh   14.90% 

20  mesh    10.27% 

35  mesh   22.42% 

65  mesh 6.98% 

100  mesh   0.96% 

150  mesh    1.32% 

Passed  150  mesh  43.15% 

Plasticity    Good 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage    6.92% 

Tempering  water   23.40% 

Oxidation Difficult,  90%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range.  .  .Temperature  not  carried  high  enough  to  determine  this. 
When  burned  at  cone  5 — 

Burning  shrinkage   6.97% 

Total   shrinkage    13.89% 

Porosity     12.24% 

Fracture  Stony,  shows  numerous  black  specks. 

Color Buff  at  cone  010,  gray  buff  at  cone  04,  gray  at  cone  5. 

Possibilities    Common  and  front  brick,  hollow  blocks, 

fireproofing.  Though  difficult  to  oxi- 
dize at  650°  C,  the  clay  remains  suffi- 
ciently porous  above  900 °C  so  that 
oxidation  progresses  without  danger. 

Sample  34. — Location  in  mine,  two-thirds  mile  out  on  SE.  entry;  sample 
represents  floor  material  from  20  to  36  inches  below  coal,  the  material  from  0 
to  11  inches  below  coal  was  a  black  clay,  the  clay  from  11  to  20  inches  was  not 
tested;  structure  of  sample  characteristically  that  of  fire  clay;  dark-blue  gray; 


LABORATORY  TESTS  53 

numerous  well-developed  slickensides ;  contains  carbon  as  plant  fossils  and  nod- 
ules of  altered  pyrite. 

Slaking  test   Slakes  in  147  hours. 

Residues  left  on  screens — 

10  mesh   17.35% 

20  mesh   14.60% 

35  mesh  21.40% 

65  mesh   18.70% 

100  mesh   7.78% 

150  mesh  3.38% 

Passed  150  mesh  16.79% 

Plasticity   Good 

Molding  properties  Good 

Drying  properties  Good 

Linear  drying   shrinkage 6.01% 

Tempering  water    24.06% 

Oxidation  Complete  in  14  hours. 

Maximum   safe  burning  temperature Cone  3 

Heat  range  Cone    04    to    cone    3 ;    bloating    begins 

above    cone    3 ;    clay    is    sensitve    to 
flashing. 
When  burned  at  cone  3— 

Burning  shrinkage   6.43% 

Total  shrinkage 12.44% 

Porosity     6.18% 

Fracture     Stony 

Color    Dark     buff     at     cone     010,     changes     to 

brownish    gray   at   cone   04;   no   color 
change  from  cone  04  to  cone  3. 
Possibilities Common  and  front  brick,  hollow  ware. 


LA  SALLE  COUNTY  CARBON  COAL  COMPANY,  LA  SALLE  SHAFT,  I. A  SALLE 

(Set-  fi.uure  19) 
Depth  of  shaft— 395  feet. 
Coal  bed— No.  2. 

Sample  8. — Represents  roof  material  above  coal; 
numerous  concretions  of  pyrite  and  iron  carbonate, 
cium  sulphate. 

Slaking  test  Gradually 

Residues  left  on  screens — 

10  mesh   10.80% 

20  mesh    1.55$ 

60  mesh   0.69% 

100  mesh   0.98% 

120  mesh   0.00% 

Passed   120  mesh    85.98% 

Plasticity    Good 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    5.26% 

Tempering  water    24.86% 

Oxidation   Complete  in  8  hours. 

Maximum  safe  burning  temperature Cone  01 

Heat  range Cone  02  to  cone  01  ;  bloats  above  cone  01. 


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54 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  55 

When  burned  at  cone  01 — 

Burning  shrinkage 9.48% 

Total   shrinkage    14.74% 

Porosity 1.69% 

Fracture    Vitreous,  brittle. 

Color Dark  red ;  scums  excessively. 

Possibilities    Common  brick,  hollow  ware. 

Sample  50. — Represents  roof  material  above  coal;  light-gray  shale;  con- 
tains a  little  carbonaceous  matter  and  numerous  granules  of  lime-iron  carbonate. 

Slaking  test Sample  as  received  had  been  wet  and  slaked. 

Residues  left  on  screens — 

10  mesh   1.12% 

20  mesh   5.20% 

35  mesh 7.06% 

65  mesh   5.56% 

100  mesh   2.30% 

150  mesh    1.03% 

Passed   150  mesh    77.64% 

Plasticity   Good 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage    5.15% 

Volume  drying  shrinkage   13.36% 

Tempering  water    26.50% 

Oxidation  No  trials  made. 

Maximum   safe  burning  temperature Cone  04 

Heat  range   Short ;     serious    surface    pitting    occurs 

due     to     lime-iron     granules;     bloats 
above  cone  04. 
When  burned  at  cone  04 — 

Burning  shrinkage   9.66% 

Total    shrinkage    14.81  % 

Porosity     0.73'  < 

Fracture Vitreous 

Color    Light   red   at   cone  06  to  medium   red   at 

cone  04;  scums  a  little. 

Possibilities     \u  unsafe  material  because  it  has  short 

heat  range  and  pits  excessively  at  the 
surface. 

Sample  17. — Represents  floor  material  below  coal;  medium  hard,  dark  slate- 
gray  fire  clay;  shows  well-developed  slickensides ;  contains  pyrite,  carbonaceous 
matter  as  plant  fossils,  and  traces  of  gypsum. 

Slaking  test   Slakes  rapidly  to  a  plastic  mass. 

Residues  left  on  screens — 

10  mesh   24  50' ', 

20  mesh    6.70^5 

60  mesh    6.40'  < 

100  mesh    0.84% 

120  mesh 0.93% 

Passed  120  mesh  61 .5(>'  '< 

Plasticity   Good 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage    11.46% 

Volume  drying  shrinkage    37. 82*  - 

Tempering  water    28.42% 

Oxidation I  )ifficult,  62*  <    oxidized  in  9  hours. 

Maximum   safe  burning  temperature Above  cone  3. 


56  CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 

Heat  range  Temperature  not  carried  high  enough  to 

determine    this ;     fusion    temperature, 
cone  29^  (1720°C). 
When  burned  at  cone  3 — 

Burning  shrinkage   6.75% 

Total   shrinkage    18.21% 

Porosity     10.40% 

Fracture     Stony 

Color Light  buff ;  scums  slightly. 

Possibilities    Common  and  building  brick,  fireproof- 

ing,  and  as  a  bond  clay  for  No.  2  fire 
brick ;  when  washed  and  screened  it 
may  be  used  for  stoneware.  The  clay 
remains  porous  up  to  a  comparatively 
high  temperature,  hence  can  be  oxi- 
dized easily. 

MATTHIESSEN  &  HEGELER  ZINC  COMPANY,  M.  &  H.  MINE,  LA  SALLE 

(See  figure  20) 
Depth  of  shaft— 310  feet. 
Coal  bed — No.  2. 

Sample  47. — Location  in  mine,  300  yards  from  shaft  beyond  stable ;  sample 
represents  roof  material  up  to  24  inches  above  coal ;  mixture  of  hard,  dark-gray 
and  dull-black  shale  with  occasional  conchoidal  lumps  of  very  light-weight  black 
material  resembling  cannel  coal  and  burning  readily  in  a  gas  flame ;  the  gray 
shale  contains  occasional  streaks  of  carbonaceous  matter  and  the  black  shale 
contains  a  high  percentage  of  finely  distributed  carbon. 

Slaking  test   Very  little  affected. 

Residues  left  on  screens.  .  .Practically  all  remained  on  10-mesh  screen. 

Plasticity   Fair 

Molding  properties Slightly  difficult  to  work  in  the  die,  tears 

a  little  at  the  corners. 

Drying  properties  Good 

Linear  drying  shrinkage 2.83% 

Tempering  water  18.80% 

Oxidation Difficult,  91%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  02 

Heat  range Cone  04  to  cone  02 ;  bloats  above  cone  02. 

When  burned  at  cone  02 — 

Burning  shrinkage   10.48% 

Total  shrinkage 13.31  % 

Porosity     6.50% 

Fracture  Dull,  dense. 

Color  Dark  red. 

Possibilities    A  dangerous   material    as   it   is   difficult 

to  mold,  difficult  to   oxidize,   high   in 
carbon,  sensitive  to  bloating. 
Sample  80. — Location  in  mine,  200  yards  from  shaft  on  SW.  entry ;  sample 
represents  roof  shale  up  to  5  feet  above  coal ;  dull  black;  medium  soft;  principally 
carbonaceous  matter  containing  a  noticeable  amount  of  pyrite. 

Slaking  test   Does  not  slake. 

Residues  left  on  screens All  on  10-mesh  screen. 

Plasticity   Lacking 

Molding  properties.  .Impossible  to  mold,  hence  no  briquets  were  made. 

Possibilities    Impossible   material    for   clay   products, 

as  it  is  excessively  high  in  carbon- 
aceous matter,  devoid  of  plasticity, 
and  impossible  to  mold  in  die. 


LABORATORY  TESTS  57 


ILLINOIS  ZINC  COMPANY,  BLACK  HOLLOW  MINE,  OGLESBY 
(See  figure  21) 
Kind  of  mine — Slope. 
Area  mined — 85  to  100  acres. 
Coal  bed — No.  2. 

Sample  12. — Sent  by  company ;  sample  represents  roof  material  above  coal ; 
hard,  calcareous,  light-gray  shale  streaked  with  brown ;  contains  partly  decom- 
posed pyrite,  nodules  of  calcium-iron  carbonate,  carbonaceous  matter,  and  cal- 
cium sulphate. 

Slaking  test Slakes  in  4  hours. 

Residues  left  on  screens — 

10  mesh    1.00% 

20  mesh   0.50% 

60  mesh   2.50% 

100  mesh   0.20% 

120  mesh    0.10% 

Passed  120  mesh 95.70% 

Plasticity  Good 

Molding  properties    Good 

Drying  properties  Good 

Linear  drying  shrinkage 6.24% 

Volume  drying  shrinkage    18.96% 

Tempering  water   25.39% 

Oxidation Difficult,  72%  oxidized  in  9  hours. 

Maximum  safe  burning  temperature Cone  01 

Heat    range Very  short ;  bloats  above  cone  01  ;  cracks 

in   burning;    surface   pits  due   to  cal- 
cium-iron granules. 
When  burned  at  cone  01 — 

Burning  shrinkage   10.65% 

Total  shrinkage 16.89% 

Porosity 3.25% 

Fracture    Vitreous 

Color   Dark  red  ;   scums. 

Possibilities     Very  unsuitable  material,  as  it  is  difficult 

to  oxidize,  has  short  heat  range,  cracks 
in  burning,  pits,  and  is  sensitive  to 
overfiring. 

Sample  76. — Location  of  sample,  1st  S.  160  feet  in  at  a  depth  of  109  feet; 
sample  represents  roof  material  from  0  to  24  inches  above  coal  ;  impurities,  some 
sulphur  balls;  light-gray  and  dark-gray  fragments  of  shale;  contains  gypsum, 
iron  carbonate  granules,  and  decomposed  pyrite. 

Slaking  test  Imperfectly  slaked  at  end  of  test 

Residues  left  on  screens — 

10  mesh   34.77% 

20  mesh   24.78% 

35  mesh   18.64% 

65  mesh    9.38% 

100  mesh   2.64% 

150  mesh   1.27% 

Passed  150  mesh  8.52% 

Plasticity   Fair 

Molding  properties    Good 


58 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  59 

Drying  properties  Good 

Linear  drying  shrinkage    6.84% 

Volume  drying  shrinkage    20.90% 

Tempering  water   28.30% 

Oxidation Complete  in  7  hours 

Maximum  safe  burning  temperature  Cone  04 

Heat  range  Very  short ;  bloats  above  cone  04 ;  surface  pits. 

When  burned  at  cone  04 — 

Burning  shrinkage   10.69% 

Total  shrinkage  17.53% 

Porosity     1.04% 

Fracture    Vitreous 

Color Red  brown  ;  scums. 

Possibilities  Common  brick ;  hollow  ware. 

Sample  16. — Sent  by  company ;  sample  represents  floor  material  below  coal ; 
medium  soft,  gray  clay  with  the  structure  characteristic  of  fire  clay;  slickensides 
prominent ;  contains  pyrite,  lime-iron  granules,  carbonaceous  matter  as  plant 
fossils,  and  a  trace  of  calcium  sulphate. 

Slaking  test   Slakes  in  one  hour. 

Residues  left  on  screens — 

10  mesh    0.00% 

20  mesh   1.10% 

60  mesh    0.80% 

100  mesh    0.50% 

120  mesh    0.10% 

Passed  120  mesh 98.50% 

Plasticity     High 

Molding  properties    Good 

Drying  properties High  shrinkage 

Linear  drying  shrinkage 11.42% 

Volume  drying  shrinkage    39.04% 

Tempering  water    28.43% 

Oxidation  Difficult ;  64' '/<  oxidized  in  9  hours. 

Maximum  safe  burning  temperature Above  cone  2. 

Heat  range ("one  1  to  approximately  cone  5. 

When  burned  at  cone  2 — 

Burning  shrinkage   7.90% 

Total  shrinkage  19.32% 

Porosity     2.83% 

Fracture    Stony 

Color    Buff  at  cone  010,  brownish-gray  at  cone 

03  to  cone  1 ;  scums. 

Possibilities   Common  and   front  brick,  hollow  ware. 

Precautions     Burning    should    be   done    under    strong 

oxidizing  conditions.  Though  diffi- 
cult to  oxidize  at  650°C,  the  clay  re- 
mains sufficiently  porous  above  900° C 
so  that  oxidation  continues  for  some 
time  before  the  clay  becomes  suffi- 
ciently dense  to  retard  the  action.  The 
addition   of  grog   would   be   beneficial. 


60  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


OGLESBY  COAL  COMPANY,  OGLESBY  MINE,  OGLESBY 
(See  figure  22) 
Coal  bed— No.  2. 

Sample  4. — Sent  by  company;  represents  floor  clay  of  coal;  medium  hard, 
gray  fire  clay ;  shows  well-developed  slickensides ;  contains  occasional  small  cal- 
cium carbonate  concretions,  pyrite  granules,  traces  of  calcium  carbonate,  and 
carbonaceous  matter. 

Slaking  test Slakes  in  2  hours. 

Residues  left  on  screens — 

10  mesh   0.65% 

20  mesh   0.95% 

60  mesh 0.65% 

100  mesh   0.93% 

120  mesh  0.19% 

Passed  120  mesh 96.65% 

Plasticity    High 

Molding  properties Good 

Drying  properties Warps  ;  high-drying  shrinkage. 

Linear  drying  shrinkage    10.65% 

Volume  drying  shrinkage   36.91% 

Tempering  water   29.75% 

Oxidation  Difficult,  84%  oxidized  in  9  hours. 

Maximum  safe  burning  temperature Above  cone  3 

Heat  range Good,  cone  1  to  possibly  cone  6. 

When  burned  at  cone  3— 

Burning  shrinkage   6.78% 

Total  shrinkage 17.43% 

Porosity     6.19% 

Fracture     Stony 

Color Light  buff  at  cone  010  to  gray  buff  at  cone  3. 

Possibilities Common  and  front  brick,  hollow  ware. 

Precautions  Must  be  oxidized  with  care ;  the  addi- 
tion of  sand  or  grog  (clay  calcined 
and  ground)  would  reduce  shrinkage 
and  warping. 


GRAY  &  JONES  COAL  COMPANY,  SENECA 
(See  figures  23  and  24) 

Depth  of  shaft— 130  feet. 

Area  mined — Mine  has  been  opened  but  short  distance. 

Coal  bed— No.  2. 

Thickness  of  roof — Reported  60  feet  in  some  places. 

Thickness  of  floor — Reported  to  be  12  feet. 

Impurities  in  roof — Small  bowlders  in  layers. 

Sample  42. — Location  in  mine,  straight  north  from  shaft ;  sample  repre- 
sents roof  material  up  to  6  feet  above  coal ;  medium  hard,  light-gray  shale 
stained  brown  in  spots ;  contains  streaks  of  pyrite  and  calcium  sulphate,  appar- 
ently free  from  carbon. 


LABORATORY  TESTS  61 

Slaking  test Very  little  affected. 

Residues  left  on  screens — 

10  mesh   70.12% 

20  mesh   8.70% 

35  mesh   6.80% 

65  mesh   4.48% 

100  mesh   1.70% 

150  mesh   0.84% 

Passed  150  mesh 7.36% 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    4.44% 

Tempering  water   22.20% 

Oxidation  Complete  in  10  hours. 

Maximum  safe  burning  temperature Cone  04 

Heat  range Very  short,  bloats  above  cone  04. 

When  burned  at  cone  04 — 

Burning  shrinkage   8.22% 

Total    shrinkage    12.66% 

Porosity     0.56% 

Fracture    Vitreous 

Color  Medium  red,  scums  very  badly. 

Possibilities Common  brick  and  hollow  ware. 

Precautions Should   be   burned    at   safe   limit   below 

bloating  temperature ;  would  require 
considerable  care  during  oxidation 
stage  of  the  burn. 

Sample  48. — Location  in  mine,  2d  R.  entry;  sample  represents  roof  material 
up  to  7  feet  above  coal ;  medium  hard,  light-gray  shale  stained  brown  in  spots  ; 
contains  some  calcium  sulphate  and  numerous  hard,  clay-like  concretions  of 
calcium  carbonate  streaked  with  pyrite. 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    90.42% 

20  mesh    2.95% 

35  mesh   2.00% 

65  mesh   1.22% 

100  mesh   0.45% 

150  mesh   0.25% 

Passed  150  mesh  2.71% 

Plasticity   Fair 

Molding   properties    Fair 

Drying  properties  Good 

Linear  drying   shrinkage    3.63% 

Volume  drying  shrinkage    11.25% 

Tempering  water   16.30% 

Oxidation  Complete  in  6  hours. 

Maximum  safe  burning  temperature Cone  02 

Heat  range Cone  04  to  cone  02 ;  surface  pits  very  numerous. 

When  burned  at  cone  02 — 

Burning  shrinkage   8.80% 

Total   shrinkage    12.43%. 

Porosity     0.69% 

Fracture    Vitreous 

Color   Dark  red,  scums  excessively. 

Possibilities Common  brick  and  hollow  blocks. 


62 


CLAY  MATERIALS   IN  ILLINOIS   COAL  MINES 


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LABORATORY  TESTS  63 

Sample  51. — Location  in  mine,  NW.  room,  No.  4  sump ;  sample  tested  com- 
posed of  a  mixture  of  two  samples  of  floor  material,  one  from  0  to  38  inches 
below  coal,  the  other  from  38  to  45  inches  below  coal  at  same  place ;  light-gray, 
partly  slaked  clay;  contains  sulphur  balls  next  to  coal,  pyrite,  lime  concretions, 
granules  of  iron  carbonate,  finely  divided  lime,  and  a  small  amount  of  carbon- 
aceous matter  as  fragments  of  coal. 

Slaking  test Complete  in  12  hours. 

Residues  left  on  screens  — 

10  mesh   1.01% 

20  mesh 6.22% 

35  mesh 22.95% 

65  mesh   13.50% 

100  mesh 4.59% 

150  mesh   3.13% 

Passed  150  mesh  : 48.607c 

Plasticity Very  good 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    10.53% 

Volume  drying  shrinkage    30.76% 

Tempering  water    : 27.44% 

Oxidation Complete  in  5  hours. 

Maximum  safe  burning  temperature Cone  3 

Heat  range  Cone  02  to  cone  3 ;  bloats  above  cone  3  ; 

surface    pits    occur    due    to    lime-iron 
granules ;  cracks  in  burning. 
When  burned  at  cone  3 — 

Burning  shrinkage   6.51', 

Total   shrinkage    17.04' , 

Porosity     2.71% 

Fracture     Stony 

Color    Light    buff    at    cone    010 ;    changes    to 

greenish-gray  at  cone  03;  scums. 

Possibilities    Not   desirable    for  manufacture  of  clay 

products  because  of  cracking  in  burn- 
ing, surface  pitting,  and  scumming. 

Sample  52. — Location  in  mine,  NE.  entry  in  sump  ;  sample  represents  floor 
material  from  12  to  36  inches  below  coal  ;  similar  to  Sample  51,  but  contains  less 
lime  and  iron  carbonate  granules. 

Slaking  test   Complete  in   13  hours. 

Residues  left  on  screens — 

10  mesh   4.85', 

20  mesh    9.00% 

35  mesh   18.65% 

65  mesh    12.2))', 

100  mesh    6.17% 

150  mesh   7.33% 

Passed   150  mesh    41.80% 

Plasticity   Good 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage    8.477' 

Tempering  water    23.70' , 

Oxidation  Complete  in  5  hours. 

Maximum  safe  burning  temperature ( "one  3 

Heat  range Cone  02  to  cone  3  ;  few  surface  pits  oc- 
cur ;   cracks   in   burning. 


64 


CLAY  MATERIALS   IN  ILLINOIS   COAL  MINES 


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LABORATORY  TESTS  65 

When  burned  at  cone  3 — 

Burning  shrinkage   5.25% 

Total  shrinkage 13.72% 

Porosity     8.07% 

Fracture     Stony 

Color.  .  .  .Buff  at  010,  changes  to  greenish-gray  at  cone  03;  scums. 

Possibilities    Not  a  desirable  clay  because  of  crack- 
ing, pitting,  and  scumming. 


ILLINOIS  VALLEY  COAL  COMPANY,  MINE  NO.   1,  SPARLAND 
(See  figures  25  and  26) 
Depth  of  shaft— 30  feet. 
Coal  bed — No.  7. 

Thickness  of  floor — 25   feet  in  places. 

Sample  2Q. — Outcrop  of  roof  of  coal;   sample  represents  roof  material  up 
to  30  inches  above  coal;   mixture  of   fragments  of  hard,  dark-blue  and  black 
shale  high  in  finely  divided  carbon  ;  contains  calcium-iron  carbonate  concretions. 
Section  of  material  sampled — 

4.     Shale,  soft     6  inches 

3.     Shale,  black    16  inches 

2.     Shale,  gray    6  inches 

1.     Shale,  black    12  inches 

Slaking  test   Slakes  very  imperfectly. 

Residues  left  on  screens— 

10  mesh   83.0O%> 

20  mesh   4.107o 

35  mesh   3.73% 

65  mesh   2.55% 

100  mesh   1.08% 

150  mesh    0.60% 

Passed  150  mesh  4.94% 

Plasticity    Low 

Molding  properties Fair 

Drying  properties  Warps 

Linear  drying  shrinkage 5.21% 

Tempering  water    22.70% 

Oxidation  No  trials  made. 

Maximum  safe  burning  temperature Cone  04 

Heat  range Very  short ;  surface  pits  due  to  calcium- 
iron  granules  ;  bloats  above  cone  04. 
When  burned  at  cone  04 — 

Burning  shrinkage   10.90% 

Total  shrinkage 16.11% 

Porosity    8.17% 

Fracture    Vitreous 

Color Light  cherry  red  ;  free  from  scum. 

Possibilities     A  very  unsuitable  material,  as  it  warps 

in  drying,  has  short  heat  range,  pits, 
and  is  sensitive  to  firing. 


66  CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 

Sample  jo. — Outcrop  of  roof  of  coal ;  sample  represents  roof  material  from 
30  to  66  inches  above  coal ;  soft,  weathered,  yellow  shale  in  small  fragments ; 
contains  carbonaceous  matter,  gives  test   for  calcium  sulphate. 

Slaking  test  Showed  no  evidence  of  slaking. 

Residues  left  on  screen All  on  10-mesh  screen. 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    2.91% 

Tempering  water    26.10% 

Oxidation  Complete  in  8  hours. 

Maximum  safe  burning  temperature Cone  1 

Heat  range Good,  cone  04  to  cone  1  ;  bloats  above  cone  1. 

When  burned  at  cone   1 — 

Burning  shrinkage   10.37% 

Total   shrinkage    13.64% 

Porosity     0.45% 

Fracture   Vitreous 

Color   Dark  red ;  slightly  scummed. 

Possibilities Common  and  face  brick,  hollow  ware. 

Sample  49. — Outcrop  of  floor  clay  of  coal  No.  6;  sample  represents  floor 
material  from  18  to  78  inches  below  coal,  first  18  inches  was  discarded  because 
of  being  black  and  colored  with  iron ;  medium  hard,  light-gray  clay,  highly  cal- 
careous ;  contains  numerous  small  nodules  of  calcium  carbonate  and  carbon- 
aceous matter  as  plant  fossils. 

Slaking  test Slakes  rather  imperfectly. 

Residues  left  on  screens — 

10  mesh   83.90% 

20  mesh   6.75% 

35  mesh   2.95% 

65  mesh   1.64% 

100  mesh   0.65% 

150  mesh   0.32% 

Passed   150  mesh    3.79% 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage 5.92% 

Tempering  water    20.30% 

Oxidation  Completely  oxidized  in  7  hours. 

Maximum  safe  burning  temperature  Cone  1 

Heat  range Short ;   cracks  in  burning ;   serious  sur- 
face pitting  occurs,  due  to  lime  gran- 
ules. 
When  burned  at  cone  1 — 

Burning  shrinkage   3.61  % 

Total  shrinkage 9.53% 

Porosity 29.98% 

Fracture     Stony 

Color    Light  red  at  cone  010,  changes  abruptly 

to  dark  buff  at  cone  03,  and  to  a  light 
buff  at  cone  3. 

Possibilities    A    very    unsuitable    material    as    it    has 

short    heat    range,    cracks    in   burning, 
pits,  and  is  sensitive  to  overfiring. 


LABORATORY  TESTS  67 

Sample  70. — Outcrop  of  floor  clay  of  coal  No.  6;  sample  represents  floor 
material  from  0  to  36  inches  below  coal ;  this  material  had  been  wet  and  was 
partly  slaked ;  calcareous ;  contains  nodules  of  calcium  carbonate,  iron  carbonate, 
and  carbonaceous  matter. 

Slaking  test   Slaked  in  159  hours. 

Residues  left  on  screens — 

10  mesh    1.92% 

20  mesh   4.58% 

35  mesh 12.95% 

65  mesh   18.52% 

100  mesh 9.76% 

150  mesh   4.78% 

Passed   150  mesh    47.497c 

Plasticity    Good 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage 8.30% 

Volume  drying  shrinkage 24.80% 

Tempering  water   25.50% 

Oxidation  Difficult,  77c/c  oxidized  in  9  hours. 

Maximum  safe  burning  temperature  Cone  1 

Heat  range  Cone  02  to  cone  1  ;  surface  pits ;  cracks 

in  burning;  bloats  above  cone  1. 
When  burned  at  cone  1 — 

Burning  shrinkage   3.79% 

Total  shrinkage 12.09% 

Porosity    3.797c 

Fractu  re  Stony 

Color Buff  at  cone  010,  pale  red  at  08,  and  brown  at  02. 

Possibilities  Valueless  for  clay  products,  as  it  is  dif- 
ficult to  oxidize,  cracks  in  burning,  pits 
at  the  surface,  and  is  sensitive  to  over- 
firing. 

Sample  71. — From  same  location  as  Sample  70;  represents  floor  clay  from 
36  to  108  inches  below  coal ;  similar  to  Sample  70,  but  is  more  calcareous. 

Slaking  test   Slakes  in  51  hours. 

Residues  left  on  screens — 

10  mesh    11.60% 

20  mesh    11.35% 

35  mesh    10.86% 

65  mesh    7.517c 

100  mesh    4.15% 

150  mesh    2.187c 

Passed  150  mesh 52.35% 

Plasticity   Fai  r 

Molding  properties Good 

Drying  properties   Cracks 

Linear  drying  shrinkage 15.56% 

Tempering   water    24.30% 

Oxidation    Complete  in   8  hours. 

Maximum  safe  burning  temperature   Cone  3 

Heat  range  Very  short ;  bloats  above  cone  3  ;  cracks 

in  burning ;   surface  pits  due  to  lime 
granules. 


68  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

When  burned  at  cone  3 — 

Burning  shrinkage   2.66% 

Total   shrinkage    18.22% 

Porosity    8.93% 

Fracture     Stony 

Color    Light  salmon  at  cone  010  to  pale  red  at 

08  to  brown  at  2 ;  scums  excessively. 
Possibilities    Valueless  for  clay  products,  as  it  cracks 

in  drying  and  in  burning;   has   short 

heat   range ;    is    sensitive    to   bloating, 

pits,  and  scums. 

WENONA  COAL  COMPANY,  WENONA  MINE,  WENONA 
(See  figure  27) 
Depth  of  shaft— 567  feet. 
Coal  bed — No.  2. 

Sample  15. — Sent  by  company;  represents  roof  material  of  coal;  hard,  dark- 
gray  massive  shale ;  breaks  with  conchoidal  fracture,  apparently  free  from  car- 
bonaceous  matter  and  concretions. 

Slaking  test Apparently  does  not  slake  to  any  appreciable  extent. 

Residues  left  on  screens — 

10  mesh 99.70% 

20  mesh    0.10% 

60  mesh   0.10% 

100  mesh   0.00% 

120  mesh   0.00% 

Passed  120  mesh  0.10% 

Plasticity   Low 

Molding Tends  to  tear  a  little  in  molding,  though  not  badly. 

Drying  properties   Good 

Linear  drying  shrinkage  4.44% 

Volume  drying  shrinkage 15.01% 

Tempering  water   21.20% 

Oxidation  Complete  in  4  hours. 

Maximum  safe  burning  temperature   Above  cone  3 

Heat  range Cone  01  to  above  cone  3. 

When  burned  at  cone  3 — 

Burning  shrinkage   8.75% 

Total   shrinkage    13.19% 

Porosity 0.40% 

Fracture    Dull,  smooth. 

Color Dark  cherry  red,  free  from  scum. 

Possibilities  Common,  front,  and  paving  brick 

Precautions    Fine   grinding  and  thorough  tempering 

would    improve    the   molding   proper- 
ties ;  the  addition  of  a  small  amount 
of  suitable  plastic  clay  would  be  bene- 
ficial. 
Sample  18. — Sent  by  company ;  represents  floor  material  of  coal ;  hard,  light- 
gray  shale;  contains  carbonaceous  matter  as  plant  fossils  and  a  trace  of  calcium 
sulphate,  no  concretions  visible. 

Slaking  test Slakes  in  7  days. 

Residues  left  on  screens — 

10  mesh   2.45% 

20  mesh 5.80% 

60  mesh   5.90% 

100  mesh   0.88% 

120  mesh    0.49% 

Passed  120  mesh 84.48% 


LABORATORY  TESTS 


69 


Plasticity   Fair 

Molding  properties  Good 

Drying  properties chaw 

Linear  drying  shrinkage c'2qZ° 

Volume  drying  shrinkage    77^ 

Tempering  water   19.77% 

Oxidation  Complete  in  5  hours. 

Maximum  safe  burning  temperature   Above  cone  3. 


No.   15 

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material,  and  Sample  18,  floor  material,  in  Wenona  mine.  Wenona  Coal  Com- 
pany, Wenona. 


Heat  range Cone  1  to  above  cone  3. 

When  burned  at  cone  3 — 

Burning  shrinkage   6.92% 

Total  shrinkage 11?S<T 

Porosity 6-30% 

Fracture     Stony 

Color    Light  red  at  cone  010,  gradually  changes 

to  medium  red  at  cone  3. 

Possibilities Common,  front,  and  paving  brick,  hollow  ware. 


70 


CLAY  MATERIALS   IN   ILLINOIS   COAL  MINES 


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LABORATORY  TESTS  71 


MINONK  COAL  COMPANY,  MINE  NO.  2,   MINONK 
(See  figures  28  and  29) 
Depth  of   shaft- 540  feet. 
Coal  bed— No.  2. 

Thickness  of  floor — 6  inches  to  4  feet. 
Thickness  of  roof — 15  to  20  feet. 

Sample  84. — Location  in  mine,  NW.  4th  W. ;  sample  represents  floor  ma- 
terial from  2  to  26  inches  below  coal  (the  material  sampled  is  all  removed  in 
mining)  ;  medium  hard,  light  to  dark-blue  gray  clay ;  shows  well-developed 
slickensides ;  contains  carbonaceous  matter  and  a  trace  of  calcium  sulphate. 

Slaking  test Incompletely  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    10.45% 

20  mesh   9.66% 

35  mesh   16.50% 

65  mesh   13.65% 

100  mesh   5.95% 

150  mesh    2.44% 

Passed  150  mesh  41.81% 

Plasticity    Fair 

Molding  properties  Good 

Drying  properties  Good 

Linear  drying  shrinkage    5.95% 

Volume  drying  shrinkage    17.30% 

Tempering  water   20.00% 

Oxidation  Complete  in  5  hours. 

Maximum   safe  burning  temperature Cone  1 

Heat  range Cone  04  to  cone  1  ;  bloats  above  cone  1. 

When  burned  at  cone  1 — 

Burning  shrinkage   6.54% 

Total    shrinkage    12.49% 

Porosity     0.72% 

Fracture    Vitreous 

Color Light  brown  ;  scums  a  little. 

Possibilities Common  and  front  brick ;  hollow  ware. 

Sample  89. — Location  in  mine,  NW.  of  shaft;  sample  represents  floor  ma- 
terial from  2  to  24  inches  below  coal  No.  2;  medium  hard,  gray  clay;  structure 
resembles  that  of  fire  clay;  shows  well-developed  slickensides;  contains  carbon- 
aceous matter  as  plant  fossils  and  occasional  brown  iron  stains;  gives  test  for 
calcium  sulphate. 

Slaking  test   Incomplete  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    15.67% 

20  mesh   10.50% 

35  mesh   15.23% 

65  mesh   12.84% 

100  mesh    5.09% 

150  mesh   2.29% 

Passed  150  mesh  38.38%. 

Plasticity    Good 

Molding  properties  Good 

Drying  properties  Good 

Linear  drying  shrinkage  5.35% 

Tempering  water   21.60% 

Oxidation   Complete  in  3  hours. 


72  CLAY  MATERIALS   IN   ILLINOIS  COAL  MINES 

Maximum  safe  burning  temperature Cone  3 

Heat  range Cone  04  to  cone  3 ;  bloats  above  cone  3. 

When  burned  at  cone  3 — 

Burning  shrinkage   7.67% 

Total   shrinkage    13.02% 

Porosity     0.25% 

Fracture    Vitreous 

Color.  .  .Salmon  at  cone  010,  pale  red  at  cone  04,  brown  at  cone  3. 

Possibilities Common  and  front  brick,  hollow  ware. 

Sample  77. — Location  in  mine,  N.  14  W. ;  sample  represents  roof  material 
up  to  24  inches  above  coal;  impurities  are  sulphur  balls  and  thin  layers  of  coal; 
medium  hard,  dark-gray,  sandy  micaceous  shale ;  contains  hard  clay  concretions 
stained  brown  with  iron  oxide. 

Slaking  test  No  apparent  slaking  action  noted. 

Residues  left  on  screen All  on  10-mesh  screen. 

Plasticity    Low 

Molding   properties    . Fair 

Drying  properties Good 

Linear  drying  shrinkage    3.49% 

Tempering  water   18.60% 

Oxidation Complete  in  5  hours. 

Maximum  safe  burning  temperature Cone  01 

Heat  range Cone  04  to  cone  01  ;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage   7.13% 

Total   shrinkage    10.62% 

Porosity     5.42% 

Fracture    Dense,    stony. 

Color Dark  cherry  red ;  scums  slightly. 

Possibilities Common  and  front  brick. 

Sample  q8. — Location  in  mine,  straight  north,  main  entry ;  sample  represents 
roof  material  up  to  4  feet  above  coal ;  impurities  are  sulphur  balls  and  thin  lay- 
ers of  coal;  medium  hard,  gray  sandy  shale;  contains  hard,  clay-like  concretions 
with  an  outer  shell  and  pyrite  particles  scattered  throughout,  also  some  car- 
bonaceous matter  as  plant  fossils;  shows  test  for  calcium  sulphate. 

Slaking  test Apparently  devoid  of  slaking. 

Residues  left  on  screen All  on  10-mesh  screen. 

Plasticity    Low 

Molding  properties Molded  without  serious  trouble,  though 

there  was  a  tendency  to  tear  at  cor- 
ners on  issuing  from  the  die. 

Drying  properties   Good 

Linear  drying  shrinkage    2.83% 

Tempering  water   18.20% 

Oxidation  Complete  in  4  hours. 

Maximum  safe  burning  temperature Cone  1 

Heat  range  Cone    04   to   cone    1 ;    very   sensitive   to 

bloating  above  cone  1. 
When  burned  at  cone   1 — 

Burning  shrinkage   7.69% 

Total   shrinkage    10.52% 

Porosity     6.97% 

Fracture Dense,   stony. 

Color Dark  cherry  red ;  scums  slightly. 

Possibilities Common  and  front  brick. 


LABORATORY  TESTS  73 

Precautions    Should  be  thoroughly  tempered  in  order 

to  develop  sufficient  plasticity  for 
molding,  and  should  be  burned  at  a 
safe  temperature  below  that  at  which 
bloating  occurs. 


COLCHESTER  COAL  &  MANUFACTURING  COMPANY,  COLCHESTER 
(See  figure  30) 
Coal  bed— No.  2. 

Thickness  of  roof— Reported  to  be  10  to  30  feet 

Sample  5.— Represents   roof   material    of   coal;   hard,   gray    shale;    contains 
carbonaceous  matter  as  plant  fossils,  otherwise  rather  uniform  in  appearance. 

Slaking  test Breaks  up  into  few  coarse  fragments. 

Residues  left  on  screen All  on  10-mesh  screen. 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    4.71  % 

Volume  drying  shrinkage    13.96% 

Tempering  water   18.92% 

Oxidation  Oxidizes  readily,  complete  in  2  hours. 

Maximum  safe  burning  temperature Above  cone  3 

Heat  range. .  .Temperature  not  carried  high  enough  to  determine  this. 
When  burned  at  cone  3 — 

Burning  shrinkage   9.80% 

Total  shrinkage 14.51  % 

Porosity     0.24  % 

Fracture     Stony 

Color.  .  .Medium  red  at  cone  1,  dark  red  at  cone  3;  scums  slightly. 

Possibilities Common,  front,  and  paving  brick,  hollow  ware. 

Precautions  For  hollow  ware  the  shale  would  re- 
quire thorough  tempering  to  develop 
good  working  plasticity. 


VALENTINE  FARM   MINE,  COLCHESTER 

(Sec  figure  31) 
Coal  bed— No.  2. 

Sample  37. — Sample  represents  floor  material  below  coal;  medium  hard, 
dense  fire  clay;  contains  occasional  small  hard,  clay-like  granules;  comparatively 
free  from  carbon. 

Slaking  test   Breaks  clown  in  13  hours. 

Residues  left  on  screens — 

10  mesh   3.55% 

20  mesh    11.61% 

35  mesh   15.02% 

65  mesh   12.66% 

100  mesh   5.24% 

150  mesh    2.21%. 

Passed  150  mesh  49.71% 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    6.53% 

Tempering   water    16.70% 


74 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  75 

Oxidation    No  oxidizing  trials  made  since  the  clay 

remains  highly  porous  at  tempera- 
tures considerably  above  900°C;  no 
serious  difficulty  would  be  encountered 
during  the  oxidation  stage. 

Maximum  safe  burning  temperature Probably  above  cone  8 

Heat  range Very  broad ;  fusion  temperature  cone  29  (1710°C). 

When  burned  at  cone  3 — 

Burning  shrinkage   5.46% 

Total    shrinkage    11.99% 

Porosity     16.30% 

Fracture Stony 

Color Light  buff. 

Possibilities    Common  and  front  brick,  enamel  brick, 

architectural  terra  cotta,  fireproofing, 
and  as  a  bond  for  No.  2  fire  brick ; 
its  use  for  stoneware  is  doubtful. 


ALDEN  COAL  COMPANY,  MINE  NO.  7,  MATHERYILLE 

(See  figures  32  and  33) 
Depth  of  shaft— 95  feet. 
Area  mined — 10  acres. 
Coal  bed— No.  1. 

Sample  34. — Represents  floor  material  below  coal;  a  mixture  of  light,  blue- 
gray,  sandy  shale  and  a  very  dark  almost  black  shale  with  a  structure  resembling 
that  of  fire  clay ;  contains  carbon  and  lime-iron  concretions. 

Slaking  test  . . .  .  Slakes  in  15  hours. 

Residues  left  on  screens — 

10  mesh   56.80% 

20  mesh   8.54% 

35  mesh   10.35% 

65  mesh   7.37% 

100  mesh    2.41% 

150  mesh    1.29% 

Passed  150  mesh  13.23% 

Plasticity    Low 

Molding  properties Molds  with  difficulty;  tears  at  corners  of  die. 

Drying  properties   Good 

Linear  drying  shrinkage 4.44% 

Volume  drying  shrinkage    13.50% 

Tempering  water    19.30% 

Oxidation   Complete  in  10  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range   Temperature    not    carried    high    enough 

to  determine  this ;  surface  pits  due  to 
lime-iron  granules. 
When  burned  at  cone  5 — 

Burning  shrinkage   7.19% 

Total  shrinkage 11.63' ! 

Porosity     13.05'  fo 

Fracture     Stony 

Color    Salmon  at  cone  010,  dull  red  at  cone  03, 

brownish-gray  at  cone  5. 

Possibilities   Common  and  front  brick. 

Precautions    Works    with    difficulty   in    the    die ;    the 

addition  of  a  more  plastic  clay  and 
less  of  the  sandy  part  would  be  an 
improvement. 


76 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  77 

Sample  78. — Location  in  mine,  4th  N.  entry  on  W.  side;  sample  represents 
floor  material  from  0  to  30  inches  below  coal ;  light-gray,  decidedly  sandy  clay 
streaked  with  yellow;  contains  streaks  of  carbonaceous  matter,  mica  flakes,  and 
sulphate  of  iron. 

Slaking  test  Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens Practically  all  on  10-mesh  screen. 

Plasticity    Low 

Molding  properties  Molds  with  difficulty. 

Drying  properties Dries  with  heavy  scum  of  iron  sulphate. 

Linear  drying  shrinkage 2.62% 

Tempering  water   11.96% 

Oxidation  Complete  in  2  hours. 

Maximum  safe  burning  temperature Above  cone  3 

Heat  range.  .  .Temperature  not  carried  high  enough  to  determine  this. 
When  burned  at  cone  3 — 

Burning  shrinkage   3.45% 

Total    shrinkage    6.07% 

Porosity     26.96% 

Fracture     Stony 

Color Dark  velvet-red  surface,  salmon-color  fracture. 

Possibilities Doubtful  on  account  of  difficulties  in  molding. 

Sample  79. — Location  in  mine,  same  as  Sample  78;  sample  represents  floor 
material  from  30  to  63  inches  below  coal ;  clay  similar  to  Sample  78  except  it 
does  not  show  iron  sulphate. 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   45.32% 

20  mesh   7.50% 

35  mesh   8.18% 

65  mesh   9.057c 

100  mesh   7.07%. 

150  mesh   3.98% 

Passed  150  mesh 18.90% 

Plasticity    Low 

Molding  properties Tears  a  little  at  corners  on  issuing  from  die. 

Drying  properties   Good 

Linear  drying  shrinkage    2.69% 

Tempering  water    17.40% 

Oxidation  Complete  in  1  hour. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range. .  .Temperature  not  carried  high  enough  to  determine  this. 
When  burned  at  cone  5 — 

Burning  shrinkage   2.61% 

Total  shrinkage 5.30% 

Porosity     27.59% 

Fracture     Stony 

Color    Buff 

Possibilities Doubtful   because  of  difficulties  in  molding. 


78  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Sample  73. — Location  in  mine,  west  of  shaft  bottom ;  represents  floor  ma- 
terial from  0  to  16  inches  below  coal ;  medium  hard,  light-gray,  sandy  clay  with 
yellow  streaks;  contains  streaks  of  carbonaceous  matter  and  salts  of  iron  sul- 
phate. 

Slaking  test Slakes  slowly  and  imperfectly. 

Residues  left  on  screens — 

10  mesh   35.83% 

20  mesh   5.12% 

35  mesh   9.32% 

65  mesh   8.48% 

100  mesh   5.88% 

150  mesh    3.70% 

Passed   150  mesh    31.67% 

Plasticity   Low 

Molding  properties Though   the   plasticity   is   low,   the   clay 

molded  without  serious  trouble. 

Drying  properties Good ;  has  a  surface  scum  of  iron  sulphate. 

Linear  drying  shrinkage 3.20% 

Tempering  water   17.30% 

Oxidation Complete  in  2  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range  Burning    temperature    not    carried    high 

enough  to  determine  the  range ;  iron 
sulphate    is    converted    to    the    ferric 
oxide,   giving   a   dark  velvet-red    sur- 
face. 
When  burned  at  cone  5 — 

Burning  shrinkage   4.44% 

Total   shrinkage    7.64% 

Porosity     25.75% 

Fracture     Stony 

Color    Dark  velvet-red  surface,  whereas  a  frac- 
ture shows  salmon  color. 

Possibilities  Common  and  front  brick. 

Sample  74. — Same  location  in  mine  as  Sample  73 ;  sample  represents  floor 
material  from  16  to  38  inches  below  coal ;  decidedly  sandy,  light-gray,  dark-gray, 
and  yellow-banded  clay;  contains  streaks  of  carbonaceous  matter,  numerous 
mica  flakes,  and  iron  sulphate. 

Slaking  test   Only  slight  slaking  action. 

Residues  left  on  screens— 

10  mesh 57.50% 

20  mesh   1.43% 

35  mesh   4.67% 

65  mesh   8.21% 

100  mesh   6.18% 

150  mesh   3.87% 

Passed  150  mesh 18.14% 

Plasticity    Low 

Molding  properties Cracks  at  corners  on  issuing  from  the  die. 

Drying  properties  Dries  with  scum  of  iron  sulphate. 

Linear  drying  shrinkage 2.51% 

Volume  drying  shrinkage    7.89% 

Tempering  water    18.74% 

Oxidation  Complete  when  first  trial  was  drawn. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range  Burning   temperature    not    carried    high 

enough  to  determine  heat  range ;  iron 
sulphate  is  converted  to  ferric  oxide 
in  burning. 


LABORATORY  TESTS  79 

When  burned  at  cone  5 — 

Burning  shrinkage   2.84% 

Total  shrinkage 5.35% 

Porosity     29.69% 

Fracture     Stony 

Color v Dark  velvet-red  surface,  light-red  fracture. 

Possibilities Doubtful,  difficult  to  mold  in  the  die. 

Sample  75. — Same  location  in  the  mine  as  Samples  73  and  74 ;  sample  rep- 
resents floor  material  from  38  to  61  inches  below  coal ;  clay  similar  in  appear- 
ance to  Sample  73. 

Slaking  test  Slakes  slowly  and  imperfectly. 

Residues  left  on  screens — 

10  mesh   85.90% 

20  mesh   1.85% 

35  mesh   2.46% 

65  mesh   2.61% 

100  mesh   1.33% 

150  mesh   0.90% 

Passed  150  mesh  4.95% 

Plasticity   Low 

Molding  properties Molds  with  difficulty,  cracks  at  the  corners. 

Drying  properties Dries  with  thin  scum  of  iron  sulphate. 

Linear  drying  shrinkage 2.42% 

Tempering  water   17.30% 

Oxidation  Complete  when  first  trial  was  drawn. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range   Burning   temperature    not    carried    high 

enough  to  determine  this. 
When  burned  at  cone  5 — 

Burning  shrinkage    3.30%> 

Total  shrinkage 5.72% 

Porosity     29.637* 

Fracture     Stony 

Color Dark  velvet-red  surface,  medium  red   fracture. 

Possibilities Doubtful,  difficult  to  mold. 


PRYCE  COAL  COMPANY,  COAT.  VALLEY 
(See  figure  34) 
Depth  of  shaft— 122  feet. 
Area  mined — 10  to  12  acres. 
Coal  bed— No.  1. 

Sample  43. — Location  of  sample,  south  of  shaft;  sample  represents  floor 
material  from  4  to  18  inches  below  coal ;  sample  had  become  wet  and  slaked  ; 
light-gray,  sandy  clay;  contains  streaks  of  iron,  a  conspicuous  amount  of  iron 
sulphate  crystals,  and  fragments  of  coal. 

Slaking  test Slakes  readily  but  rather  incompletely. 

Residues  left  on  screens — 

10  mesh   2.52% 

20  mesh    6.91% 

35  mesh   14.44% 

65  mesh   15.557- 

100  mesh   11.87% 

150  mesh   4.93% 

Passed  150  mesh   43.78% 

Plasticity    Low 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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45,  and  58,  floor  materials  in  mine  of  Pryce  Coal  Company,  Coal  Valley. 


LABORATORY  TESTS  81 

Molding  properties Fair 

Drying  properties  Dries  safely  with  heavy  coating  of  sul- 
phate of  iron. 

Linear  drying   shrinkage 5.40% 

Tempering  water   17.70% 

Oxidation  Complete  in  9  hours. 

Maximum  safe  burning  temperature Considerably  above  cone  5 

Heat  range  Apparently    good ;    during    burning    the 

iron    sulphate    is    converted    to    ferric 
oxide  giving  a  rich  red  surface. 
When  burned  at  cone  5 — 

Burning  shrinkage   5.08% 

Total  shrinkage  10.48% 

Porosity 23.22% 

Fracture     Stony 

Color    Dark   velvet-red. 

Possibilities Common  and  front  brick. 

Sample  44. — Location  in  mine,  same  as  Sample  43 ;  sample  represents  floor 
material  from  18  to  32  inches  below  coal ;  clay  appears  to  be  same  as  Sample  43 
except  that  it  contains  fewer  fragments  of  coal. 

Slaking  test  Slakes  readily  though  rather  incompletely. 

Residues  left  on  screens — 

10  mesh   1.20% 

20  mesh   0.91% 

35  mesh   3.55% 

6S  mesh   19.58% 

100  mesh   9.58% 

150  mesh   7.64% 

Passed  150  mesh  57.54% 

Plasticity   Fair 

Molding   properties    Good 

Drying  properties Dries   safely ;   heavy   scum   of  iron    sul- 
phate on  surface. 

Linear  drying   shrinkage    4.52% 

Volume  drying  shrinkage    13.00% 

Tempering  water    18.05% 

Oxidation   Complete  in  10  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range  Apparently  good  ;   iron  sulphate  is  con- 
verted into   ferric  oxide  during  burn- 
ing. 
When  burned  at  cone  5 — 

Burning  shrinkage   5.46% 

Total   shrinkage    9.98% 

Porosity     23.23% 

Fracture     Stony 

Color    Dark  velvet-red. 

Possibilities    Common  and  front  brick. 

Sample  45. — Location  in  mine,  same  as  Samples  43  and  44;  sample  repre- 
sents floor  material  from  32  to  48  inches  below  coal ;  clay  very  similar  to  Sam- 
ples 43  and  44  in  appearance,  though  darker  in  color. 

Slaking  test Slakes  readily  but  rather  incompletely. 


82  CLAY  MATERIALS   IN  ILLINOIS  COAL  MINES 

Residues  left  on  screens — 

10  mesh   3.05% 

20  mesh    5.06% 

35  mesh   11.34% 

65  mesh   17.40% 

100  mesh   8.30% 

150  mesh   5.36% 

Passed  150  mesh 49.49% 

Plasticity Fair 

Molding  properties  Molds  without  difficulty. 

Drying  properties Good;  surface  scums  with  iron  sulphate. 

Linear  drying  shrinkage 4.62% 

Volume  drying  shrinkage   13.80% 

Tempering  water   18.60% 

Oxidation  Complete  in  10  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range  Apparently  good ;  iron  sulphate  changed 

to  ferric  oxide  in  burning. 
When  burned  at  cone  5 — 

Burning  shrinkage 6.63% 

Total  shrinkage 11.25% 

Porosity     17.23% 

Fracture     Stony 

Color    Dark  velvet-red. 

Possibilities Common  and  front  brick. 

Sample  58. — Location  in  mine,  150  yards  southeast  of  shaft ;  sample  repre- 
sents floor  material  from  8  to  20  inches  below  coal ;  light-gray  clay  increasingly 
sandy  with  depth  ;  contains  occasional  fragments  of  coal  and  granules  of  lime- 
iron  carbonate. 

Slaking  test Slakes  in  11  hours. 

Residues  left  on  screens — 

10  mesh   7.37% 

20  mesh   4.59% 

35  mesh   21.40% 

65  mesh   19.96% 

100  mesh   6.95% 

150  mesh   5.16% 

Passed  150  mesh  34.57% 

Plasticity   Good 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage   5.35% 

Volume  drying  shrinkage   17.40% 

Tempering  water   23.00% 

Oxidation  Complete  in  3  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range  Cone    04    to    above    cone    5 ;    occasional 

surface    pits    occur   due    to    lime-iron 
granules. 
When  burned  at  cone  5 — 

Burning  shrinkage  8.60% 

Total    shrinkage    13.95% 

Porosity     1.04% 

Fracture    Dense,   stony. 

Color    Light  buff  at  cone  010,  changes  abruptly 

to  light  brown  at  cone  04,  and  remains 
constant  to  cone  5. 
Possibilities Common  and  front  brick,  firep  roofing,  hollow  ware. 


LABORATORY  TESTS  83 


MANUFACTURERS  &  CONSUMERS  COAL  COMPANY,  MINE  NO.   1,  DECATUR 

(See  figure  35) 
Depth  of  shaft— 575   feet. 
Coal  bed — No.  5. 
Thickness  of  roof — Irregular. 
Thickness  of  floor — About  4  feet. 

Sample  69. — Location  in  mine,  main  W.  2,450  feet;  sample  represents  roof 
material  from  26  to  68  inches  above  coal ;  medium  hard,  calcareous,  mottled 
light-brown  and  gray  shale ;  contains  hard  clay  concretions,  fine  pyrite  grains, 
iron  carbonate,  and  gypsum. 

Slaking  test    Slakes  imperfectly. 

Residues  left  on  screens — 

10  mesh  47.60% 

20  mesh 11.00% 

35  mesh  9.02% 

65  mesh   5.71% 

100  mesh   2.21% 

150  mesh   1.29% 

Passed  150  mesh  23.17% 

Plasticity  Medium 

Molding  properties Fair 

Drying  properties Warps 

Linear  drying  shrinkage 6.85% 

Volume  drying  shrinkage 19.56% 

Tempering  water   27.60% 

Oxidation  Complete  in  6  hours. 

Maximum  safe  burning  temperature  Cone  04 

Heat  range  Cone  06  to  cone  04 ;  surface  pits ;  bloats 

above  cone  04. 
When  burned  at  cone  04 — 

Burning  shrinkage   6.73% 

Total  shrinkage 13.58% 

Porosity 0.47% 

Fracture    Vitreous 

Color Medium  red ;  scums  badly 

Possibilities    Common     brick ;     its     use     for     hollow 

blocks  is  doubtful  because  of  warping. 

Sample  oj. — Location  in  mine,  100  feet  from  air  shaft;  sample  represents 
floor  material  from  24  to  48  inches  below  coal ;  material  had  been  slaked ;  light- 
gray  clay  streaked  with  dark  gray  and  yellow ;  contains  partly  decomposed  py- 
rite, gypsum,  and  free  sulphur;  very  little  carbonaceous  matter  visible. 

Slaking  test Slakes  in  159  hours. 

Residues  left  on  screens — 

10  mesh   7.36%, 

20  mesh   1.52% 

35  mesh   3.10% 

65  mesh   9.03% 

100  mesh    5.82% 

150  mesh   2.78% 

Passed  150  mesh  70.39% 

Plasticity   Good 

Molding  properties  Good 


84 


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LABORATORY  TESTS  85 

Drying  properties Good  ;  scums 

Linear  drying  shrinkage 9.30% 

Tempering  water   27.30% 

Oxidation  Complete  in  9  hours 

Maximum  safe  burning  temperature    Cone  06 

Heat  range  Very   short ;    cracks   in   burning ;    bloats 

above  cone  06. 
When  burned  at  cone  06 — 

Burning  shrinkage   5.80% 

Total   shrinkage    15.10% 

Porosity     6.31% 

Fracture      Vitreous 

Color  Dull,  medium  red ;  scums. 

Possibilities    A    very    unsuitable    material    as    it    has 

short  heat  range,  cracks  in  burning, 
and  is  sensitive  to  overfiring  and 
bloating. 

Sample  96. — Location  in  mine,  8th  S.  off  main  W. ;  sample  represents  floor 
material  from  8  to  24  inches  below  coal ;  medium  hard,  gray  clay  stained  brown 
in  streaks;  structure  is  that  of  fire  clay;  contains  occasional  carbonate  of  iron 
granules  and  carbonaceous  matter  as  plant  fossils. 

Slaking  test Slakes  in  9  hours. 

Residues  left  on   screens — 

10  mesh    1.53% 

20  mesh   0.40% 

35  mesh  0  50% 

65  mesh   0.657^ 

100  mesh    0.52% 

150  mesh   0.37% 

Passed  150  mesh  96.03% 

Plasticity     High 

Molding  properties Good 

Drying  properties   Good 

Linear  drying  shrinkage    9.747 

Tempering  water   20.40%> 

Oxidation   Difficult ;  587    oxidized  in  14  hours. 

Maximum  safe  burning  temperature   Cone  1 

Heat    range    Cone  04  to  cone   1  ;   occasional   surface 

pits  occur;  bloats  above  cone  1. 
When  burned  at  cone   1 — 

Burning  shrinkage   5.77% 

Total  shrinkage 15.51% 

Porosity 5.93% 

Fracture   Dense,  stony 

Color    Buff  at  cone  08,  to  gray  brown  at  cone 

04,  color  constant  to  cone  1. 

Possibilities    Common  and  front  brick,  hollow  blocks, 

and  fireproofing. 

Precautions     Care  must  be  taken  during  the  oxidation 

period  in  burning. 


86  CLAY  MATERIALS  IN  ILLINOIS   COAL  MINES 


DECATUR  COAL  COMPANY,  NIANTIC  MINE,  NIANTIC 

(See  figure  36) 
Depth   of  shaft— 612   feet. 
Coal  bed — No.  5. 

Sample  33. — Sent  by  company;  sample  represents  36  inches  of  floor  clay; 
medium  soft,  calcareous,  light-gray  shale  stained  brown  in  spots ;  contains  car- 
bonaceous matter  as  plant  fossils  and  nodules  of  calcium-iron  carbonate. 

Slaking  test   Slakes  in  15  hours. 

Residues  left  on  screens — 

10  mesh   3.03% 

20  mesh   5.20% 

35  mesh   7.69% 

65  mesh   5.24% 

100  mesh   0.84% 

150  mesh   0.90% 

Passed  150  mesh 77.10% 

Plasticity    Good 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage  8.84% 

Tempering  water    18.40% 

Oxidation Difficult,  52%  oxidized  in  14  hours. 

Heat   range    Very  short ;   bloats  above   cone   08 ;    at 

cone   04   trial   pieces   are    10%    larger 
than  before  burning;  surface  pits. 
When  burned  at  cone  08 — 

Burning  shrinkage   6.80% 

Total  shrinkage 15.64% 

Porosity  3.98% 

Fracture     Stony 

Color  Dull  red 

Possibilities    An  unsafe  material,  as  it  is  difficult  to 

oxidize,  has  high  lime  content  and 
short  heat  range,  pits,  and  is  sensitive 
to  bloating. 


LABORATORY  TESTS  87 


McLEAN  COUNTY  COAL  COMPANY,  McLEAN  mine,  bloomington 
(See  figures  37  and  38) 
Depth  of  shaft— 530  feet  to  coal  No.  2;  400  feet  to  coal  No.  5. 
Coal  beds— No.  2  and  No.  5. 

Thickness  of  roof  of  coal  No.  2 — Varies  from  0  to  15  feet. 
Thickness  of  floor  of  coal  No.  2 — More  than  9  feet  is  known. 
About  60  tons  of  shale  is  being  mixed  daily  with  30  tons  of  burned  dump 
for  manufacture  of  30,000  brick;  for  building  tile,  only  shale  is  used. 

Sample  59. — Location  in  mine,  1st  S.  on  straight  W. ;  sample  represents  roof 
material  from  0  to  6  feet  above  coal  No.  2;  medium  hard,  light-gray  shale 
streaked  with  brown  stains ;  contains  occasional  hard,  clay-like  concretions. 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh  81.20% 

20  mesh   7.62% 

35  mesh   4.83% 

65  mesh 2.39% 

100  mesh   0.73% 

150  mesh   0.30% 

Passed   150  mesh   2.93% 

Plasticity   Fair 

Molding  properties  Good 

Drying  properties  Good 

Linear  drying  shrinkage 4.89% 

Volume  drying  shrinkage    16.40% 

Tempering  water   22.40% 

Oxidation  Complete  in  9  hours. 

Maximum  safe  burning  temperature  Cone  04 

Heat  range  Short  ;  bloats  above  cone  04 

When  burned  at  cone  04 — 

Burning  shrinkage   7.42% 

Total  shrinkage 12.31% 

Porosity 1.49% 

Fracture    Vitreous 

Color Dull,  light  red  at  cone  06,  dark  red  at  cone  04. 

Possibilities  Common  brick,  hollow  ware. 

Precautions     Must     be     completely     oxidized     below 

90° C;  owing  to  short  heat  range,  con- 
siderable variation  in  shrinkage,  por- 
osity, and  color  of  product  from  kiln 
would  result. 

Sample  66. — Location  in  mine,  beginning  of  slope  to  upper  coal;  sample  rep- 
resents roof  material  from  9  feet  6  inches  to  11  feet  6  inches  above  coal  No.  2; 
medium  hard,  gray  shale  with  occasional  brown  streaks ;  contains  some  finely 
distributed  calcium  carbonate. 

Slaking  test    No   slaking  action  noticeable. 

Residues  left  on  screens — 

10  mesh   100.00% 

Plasticity   Fair 

Molding  properties  Fair 

Drying  properties   Good 

Linear  drying  shrinkage 3.04% 

Tempering  water    22.76% 

Oxidation  Complete  in  6  hours. 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  89 

Maximum  safe  burning  temperature  Cone  04 

When  burned  at  cone  04 — 

Burning  shrinkage  8.53% 

Total  shrinkage  11.57% 

Porosity 0.36% 

Fracture    Vitreous 

Color Cherry  red ;  scums  slightly. 

Possibilities   Common  and  front  brick. 

Precautions    It  would  be  necessary  to  burn  the  shale 

at  a  safe  temperature  below  that  at 
which  bloating  takes  place ;  a  product 
of  variable  shrinkage,  porosity,  and 
color  would  result. 

Sample  56. — Location  in  mine,  7,000  feet  straight  N. ;  sample  represents  floor 
material  from  12  to  28  inches  below  coal  No.  2;  medium  hard,  dark,  slate-gray 
clay ;  contains  gypsum,  occasional  lime  concretions,  and  carbonaceous  matter  as 
plant   fossils. 

Slaking  test Slaking  action  ceases  at  the  end  of  27  hours. 

Residues  left  on  screens — 

10  mesh   6.66% 

20  mesh   4.37% 

35  mesh   20.36% 

65  mesh   25.43% 

100  mesh   9.26% 

150  mesh    4.76% 

Passed  150  mesh 29.16% 

Plasticity    Good 

Molding  properties  Good 

Drying   properties    Good 

Linear  drying  shrinkage 7.26% 

Tempering  water   22.16% 

Oxidation   Difficult ;  60%  oxidized  in   12  hours. 

Maximum   safe  burning  temperature Cone  1 

Heat  range  Cone  04  to  cone  1  ;  bloats  above  cone  1  ;  cracks. 

When  burned  at  cone   1 — 

Burning  shrinkage   7.21  % 

Total  shrinkage  14.47% 

Porosity     1.78%' 

Fracture   Dense,  stony 

Color Dull,  reddish  brown  ;  scums  slightly. 

Possibilities    Not  a  safe  material,  as  it  is  difficult  to 

oxidize  and  tends  to  crack  in  burning. 

Sample  57. — Location  in  mine,  same  as  Sample  56 ;  represents  floor  material 
from  28  to  46  inches  below  coal  No.  2 ;  very  similar  in  appearance  and  working 
properties  to  previous  sample. 

Slaking  test   Slakes  in   13  hours. 

Residues  left  on   screens — 

10  mesh   0.77% 

20  mesh   3.04% 

35  mesh   10.88% 

65  mesh   39.80% 

100  mesh   5.61% 

150  mesh   6.41%; 

Passed  150  mesh  33.49% 

Plasticity    Good 

Molding  properties Good 


90  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Drying  properties Good 

Linear  drying  shrinkage 7.29% 

Volume  drying  shrinkage 22.80% 

Tempering  water   20.40% 

Oxidation  Difficult,  66%  oxidized  in  13  hours. 

Maximum  safe  burning  temperature  Cone  1 

Heat  range  Cone  04  to  cone  1 ;  bloats  above  cone  1 ; 

tends  to  crack. 

When  burned  at  cone  1 — 

Burning  shrinkage   7.55% 

Total   shrinkage    14.84% 

Porosity     2.03% 

Fracture   Dense,  stony 

Color Dull  reddish  brown ;  scums  slightly. 

Possibilities    Not  a  safe  material,  as  it  is  difficult  to 

oxidize  and  tends  to  crack  in  burning. 

Sample  64. — Location  in  mine,  300  feet  E.  of  drop  shaft ;  sample  represents 
floor  material  from  4  to  30  inches  below  coal  No.  5;  a  mixture  of  light-gray  and 
blue  shale ;  the  light-gray  shale  is  decidedly  calcareous,  the  blue  shale  appears 
to  be  free  from  lime  but  contains  carbon  and  streaks  of  pyrite  and  is  stained 
brown   in  spots. 

Slaking  test   Slakes  in  1 1  hours. 

Residues  left  on  screens — 

10  mesh   3.20% 

20  mesh   6.57% 

35  mesh   14.75% 

65  mesh   14.69% 

100  mesh   8.58% 

150  mesh   4.26% 

Passed  150  mesh  47.95% 

Plasticity Medium 

Molding   properties    Fair 

Drying  properties   Good 

Linear  drying  shrinkage 8.79% 

Tempering  water   28.40% 

Oxidation Difficult,  56%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature  Cone  08 

Heat  range  Cone  010  to  cone  08 ;  bloats  above  cone 

08;    at   cone   04  the  trials   are   larger 
than  before  burning ;  cracks  in  burn- 
ing. 
When  burned  at  cone  08 — 

Burning  shrinkage   7.07% 

Total    shrinkage    15.86% 

Porosity  3.02% 

Fracture Stony 

Color   Light  red,  scums  slightly. 

Possibilities  A  very  unsuitable  material  as  it  is  dif- 
ficult to  oxidize,  cracks  in  burning, 
and  is  sensitive  to  overfiring  and 
bloating. 


LABORATORY  TESTS  91 


WABASH  COAL  COMPANY,  MINE  NO.  2,  ATHENS 
(See  figure  39) 
Coal  bed — No.  5. 

Sample  o. — Location  in  mine,  3,000  feet  from  shaft;  sample  represents  floor 
material;  hard,  gray,  slightly  calcareous  shale,  full  of  small  concretions  of  cal- 
cium carbonate  and  partly  decomposed  pyrite. 

Slaking  test Slakes  in  1  hour. 

Residues  left  on  screens — 

10  mesh   16.00% 

20  mesh   1.90% 

60  mesh  9.10% 

100  mesh   1.40% 

120  mesh   0.10% 

Passed   120  mesh    71.50% 

Plasticity    Good 

Molding  properties  Good 

Drying  properties  Warps 

Linear  drying  shrinkage 10.95% 

Volume  drying  shrinkage    36.38% 

Tempering  water    30.66% 

Oxidation No  tests  made. 

Maximum  safe  burning  temperature  Cone  02 

Heat  range  Cone  06  to  cone  02 ;  cracks  in  burning ; 

surface    pits    due    to    hydration    and 
swelling     of     lime     granules;     bloats 
above  cone  02. 
When  burned  at  cone  02 — 

Burning  shrinkage   5.16% 

Total   shrinkage    16.11% 

Porosity  21.55% 

Fracture    Vitreous 

Color   Dark  red  to  greenish  brown. 

Possibilities    \n  unsafe  material,  as  it  warps  in  dry- 
ing, cracks  in  burning,  and  pits. 

Sample  38,. — Represents  floor  material  of  coal ;  sample  as  sent  by  company 
had  been  wet  and  had  slaked  to  a  soft,  earthy,  granular  mass  ;  contains  granules 
of  calcium  carbonate,  pyrite,  and  carbonaceous  matter. 

Slaking  test  Slakes  readily. 

Residues  left  on  screens — 

10  mesh    1.20% 

20  mesh   8.23% 

35  mesh   24.40% 

65  mesh   15.83% 

100  mesh   673% 

150  mesh   3.79% 

Passed   150  mesh    39.87% 

Plasticity    Good 

Molding  properties  Good 

Drying  properties   Cracks 

Linear  drying  shrinkage    8.11% 

Tempering  water   24.30% 

Oxidation Difficult,  57%  oxidized  in  14  hours. 


92 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  93 

Maximum  safe  burning  temperature  Cone  06 

Heat    range    Short ;   bloating  occurs   above  cone  06 ; 

cracks  in  burning. 
When  burned  at  cone  06 — 

Burning  shrinkage   3.08% 

Total    shrinkage    11.19% 

Porosity     1 1.64% 

Fracture     Stony 

Color  Dull  red 

Possibilities    Of  no  practical  value ;  a  very  unsuitable 

material  as  it  cracks  in  drying,  is  dif- 
ficult to  oxidize,  cracks  and  bloats  in 
burning,  and  has  short  heat  range. 


CLARK,  COAL  &  COKE  COMPANY,   MINE  NO.  2,  PEORIA 
(See  figure  40) 
Depth  of  shaft— 186  feet. 
Coal  bed— No.  5. 

Sample  94. — Location  in  mine,  17th  W.  off  main  S ;  sample  represents  floor 
material  from  0  to  24  inches  below  coal ;  a  mixture  of  light-gray  shale  banded 
with  dark  gray,  decidedly  calcareous  and  a  blue-gray  material  resembling  fire 
clay  in  structure  and  slightly  calcareous ;  contains  pyrite  concretions  and  car- 
bonaceous material  as  plant  fossils. 

Slaking  test   Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — ■ 

10  mesh   48.18% 

20  mesh   12.62% 

35  mesh   10.16% 

65  mesh    11.00% 

100  mesh    4.057o 

150  mesh   2.04% 

Passed  150  mesh  11.957c 

Plasticity   Fair 

Molding  properties  Good 

Drying  properties  Good 

Linear  drying  shrinkage    7.60% 

Volume  drying  shrinkage    24.20% 

Tempering   water    22.40% 

Oxidation  Difficult,  64%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature  Cone  01 

Heat    range    Cone  04  to  cone  01  ;  cracks  in  burning ; 

bloats  above  cone  01. 
When  burned  at  cone  01 — 

Burning  shrinkage   6.34% 

Total  shrinkage 13.947> 

Porosity 3.06% 

Fracture   Dense,  stony 

Color  Red  at  cone  04,  dark  brown  at  cone  01. 

Possibilities    Not  a  safe  raw  material,  as  it  is  difficult 

to   oxidize,  cracks   in   burning,   and   is 
sensitive  to  bloating. 


94  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Sample  103. — Location  in  mine,  15th  E.  off  main  S. ;  sample  represents  floor 
material  from  0  to  27  inches  below  coal  to  bedding  plane  called  the  "smooth 
parting" ;  medium  hard,  very  dark  gray  calcareous  shale  banded  with  light  gray ; 
contains  pyrite  concretions,  hard  clay-like  concretions  high  in  calcium  carbonate, 
and  some  carbonaceous  matter  as  plant  fossils. 
Section  of  material  sampled — 

1.  Clay,  very  soft 1  inch 

2.  Clay,  gray  hard   8  inches 

3.  Clay,  darker   10  inches 

4.  Clay,  gray,  hard 8  inches 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   27.43% 

20  mesh   14.98% 

35  mesh   15.68% 

65  mesh   13.54% 

100  mesh   6.25% 

150  mesh   1.76% 

Passed  150  mesh 20.36% 

Plasticity    Good 

Molding  properties Good 

Drying  properties    Warps 

Linear  drying  shrinkage 7.19% 

Tempering  water   3.70% 

Oxidation   Difficult  to  oxidize  in  13  hours. 

Maximum  safe  burning  temperature  Cone  04 

Heat  range  Short ;  cracks  in  burning ;  bloats  above  cone  04. 

When  burned  at  cone  04 — 

Burning  shrinkage   6.02% 

Total  shrinkage  13.21% 

Porosity 7.74% 

Fracture  Stony 

Color Dull  dark  red ;  scums. 

Possibilities    A  very  unsuitable  material  as  it  warps 

in  drying,  is  difficult  to  oxidize,  cracks 
in  burning,  has  short  heat  range,  and 
is  sensitive  to  overfiring. 


LABORATORY  TESTS  95 


CRESCENT  COAL  COMPANY,  MINE  NO.   1,  PEORIA 
(See  figure  41) 
Depth  of  shaft— 185   feet. 
Coal  bed— No.  5. 

Sample  65. — Location  in  mine,  3,200  feet  W.  on  main  entry ;  sample  repre- 
sents floor  material  from  0  to  24  inches  below  coal ;  dark,  slate-gray,  calcareous 
shale ;  contains  carbonaceous  matter  in  thin  seams  as  plant  fossils  and  shows 
traces  of  calcium  sulphate. 

Slaking  test  Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   53.78% 

20  mesh   12.90% 

35  mesh  10.85% 

65  mesh   7.01% 

100  mesh   3.15% 

150  mesh   1.94% 

Passed  150  mesh 10.37% 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Warps  and  cracks 

Linear  drying  shrinkage 7.36% 

Volume  drying  shrinkage    23.55% 

Tempering  water   24. 10f/r 

Oxidation    Difficult,  68%  oxidized   in   14  hours. 

Maximum  safe  burning  temperature  Cone  08 

Heat  range  Very  short ;  cracks  in  burning. 

When  burned  at  cone  08 — 

Burning  shrinkage   0.09% 

Total  shrinkage 7.45% 

Porosity 31.02% 

Fracture  Stony 

Color Pale  red ;  scums  excessively. 

Possibilities  Worthless  as  a  raw  material  for  manu- 
facturing clay  products,  as  it  warps 
and  cracks  in  drying,  is  difficult  to  ox- 
idize, cracks  in  burning,  and  scums  ex- 
cessively. 

Sample  83. — Location  in  mine,  3,700  feet  W.  of  shaft;  sample  represents 
floor  material  from  0  to  23  inches  below  coal;  medium  hard,  slate-gray  shale, 
somewhat  calcareous;  contains  streaks  of  carbonaceous  matter. 

Slaking  test  Incompletely  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    56.62% 

20  mesh   10.85% 

35  mesh    11.61% 

65  mesh   8.50% 

100  mesh   2.96% 

150  mesh    1.46% 

Passed  150  mesh   8.00% 


96 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


Plasticity   Good 

Molding  properties , Good 

Drying  properties   Cracks 

Linear  drying  shrinkage 6.48% 

Tempering  water   20.10% 

Oxidation Difficult,  62%  oxidized  in  13  hours. 

Maximum  safe  burning  temperature  Cone  01 


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floor  materials  in  mine  No.  1,  Crescent  Coal  Company,  Peoria. 


Heat  range Cone  02  to  cone  01 ;  cracks  in  burning. 

When  burned  at  cone  01 — 

Burning  shrinkage   6.72% 

Total  shrinkage 13.20% 

Porosity  7.53% 

Fracture   Dense,  stony 

Color   Dark  brown  ;  scums. 

Possibilities    A  very  unsuitable  material,  as  it  cracks 

in  drying,  is  difficult  to  oxidize,  cracks 
in  burning,  and  has  short  heat  range. 


LABORATORY  TESTS  97 


COLLIERS   COOPERATIVE  COAL  COMPANY,   MINE   NO.    1,    SOUTH    BARTONYILLE 

(See  figure  42) 
Depth  of  shaft— 130  feet. 
Coal  bed— No.  5. 

Sample  go. — Location  in  mine,  1st  N.  off  main  W. ;  sample  represents  floor 
material  from  0  to  25  inches  below  coal ;  dark,  slate-gray  shale,  banded  with 
light-gray,  medium  hard,  calcareous  shale ;  contains  pyrite  concretions  and  car- 
bonaceous  matter  in   streaks. 

Slaking  test   Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    65.00% 

20  mesh   9.45% 

35  mesh    7.42% 

65  mesh   6.76% 

100  mesh    2.29% 

150  mesh    1.45% 

Passed   150  mesh    7.63% 

Plasticity    Fair 

Molding  properties Good 

Drying  properties   Good 

Linear  drying   shrinkage    7.12'  ! 

Tempering  water    24.10% 

Oxidation   Difficult,  76%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature    Cone  01 

Heat  range Short ;  cracks  in  burning ;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage   6.97% 

Total  shrinkage  14  0(>'  { 

Porosity   0.98(  < 

Fracture   Dense,   stonj 

Color Pale  red  at  cone  010  to  brown  at  cone  02. 

Possibilities     A  very  unsuitable   raw  material,  as  it   is 

difficult  to  oxidize,  has  short  heat 
range,  cracks  in  burning,  and  is  sensi- 
tive to  bloating. 

Sample  gi. — Location  in  mine,  same  as  Sample  90;  sample  represents  from 
25  to  47  inches  of  floor  material;  medium  hard,  dark,  slate-gray  shale  similar  to 
the  previous  sample  in  appearance,  mixed  with  hard,  light-gray  shale  mottled 
with  dark  gray  and  brown;  both  shales  are  calcareous,  the  light-gray  shale  con- 
taining much  more  calcium  carbonate  than  the  dark. 

Slaking  test  Slakes  imperfectly. 

Residues  left  on  screens — 

10  mesh   69.80%^ 

20  mesh    15.20% 

35  mesh 6.25$ 

65  mesh   3  29$ 

100  mesh    1.33$ 

150  mesh    0.66$ 

Passed  150  mesh  3.65%) 

Plasticity   Fair 

Molding  properties  Good 

Drying  properties    .' Warps 

Linear  drying  shrinkage    5.20'  { 

Tempering   water    17.90% 


CLAY  MATERIALS   IN   ILLINOIS   COAL  MINES 

Oxidation Difficult,  95%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Above  cone  5 

Heat  range   Temperature  not  carried  high  enough  to 

determine  this ;   cracks  excessively  in 

burning. 


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97,  floor  materials  in  mine  No.  1,  Colliers  Cooperative  Coal  Company,  South 
Bartonville. 


When  burned  at  cone  5 — 

Burning  shrinkage   7.00% 

Total    shrinkage    12.20% 

Porosity  32.187c 

Fracture  Stony 

Color  Mottled  light  and  dark  buff. 

Possibilities    Unsafe  as  it  warps  in  drying,  is  difficult 

to  oxidize,  and  cracks  in  burning. 


LABORATORY  TESTS  99 

Sample  97. — Location  in  mine,  600  yards  from  shaft  on  main  W.  entry ; 
sample  represents  from  0  to  22  inches  of  floor  material  below  coal ;  light  and 
dark  slate-gray  lumps ;  structure  resembles  fire  clay ;  shows  occasional  slicken- 
sides ;  contains  considerable  calcareous  matter  and  much  carbonaceous  matter 
as  plant  fossils,  both  being  finely  distributed  in  streaks. 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on   screens — 

10  mesh   31.407* 

20  mesh    11.787* 

35  mesh   11.36% 

65  mesh   11.62% 

100  mesh   3.207* 

150  mesh    3.02% 

Passed  150  mesh  27.627* 

Plasticity    Good 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage  7.11% 

Volume  drying  shrinkage    22.80% 

Tempering  water   22.40% 

Oxidation  Difficult,  61%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  02 

Heat  range  Cone  04  to  cone  02 ;  cracks  in  burning ; 

bloats  above  cone  02. 

When  burned  at  cone  02 — 

Burning  shrinkage   7.11% 

Total  shrinkage 14.227* 

Porosity   5.007* 

Fracture   Dense,  stony 

Color  Dark  red. 

Possibilities    A  very  unsuitable  material,  as  it  is  diffi- 
cult to  oxidize  and  cracks  in  burning. 


CANTRALL  COOPERATIVE  (OAK  COMPANY,  CANTRALL  MINK,  CANTRALL 

(Sec  figure  43) 
Coal  bed— No.  5. 

Sample  10. — Location  in  mine,  room  south;  sample  represents  4  feet  of  roof 
material;  hard,  very  dark-brown  shale  that  breaks  into  thin  plates;  contains 
pyrite  particles  and  carbonaceous  matter  in  thin  coal  seams. 

Slaking  test Slakes  slowly. 

Residues  left  on  screens — 

10  mesh   7.70% 

20  mesh   12.507* 

60  mesh    11.507* 

100  mesh    3.00% 

120  mesh    1.707* 

Passed  120  mesh  63.607* 

Plasticity    Rather  low. 

Molding  properties  Molds  with  difficulty. 

Drying  properties   Good 

Linear  drying  shrinkage 7.67% 

Volume  drying  shrinkage    25.40% 

Tempering  water    27.45% 

Oxidation   Difficult,  72%  oxidized  in  8  hours. 

Maximum  safe  burning  temperature  Cone  03 

Heat  range    Very  short ;  bloats  above  cone  03. 


100 


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LABORATORY  TESTS  101 

When  burned  at  cone  03 — 

Burning  shrinkage   8.75% 

Total  shrinkage 16.42% 

Porosity 16.16% 

Fracture    Coarse,  stony 

Color  Bright  cherry  red 

Possibilities    Not  a  safe  material  as  it  is  difficult  to 

mold,  difficult  to  oxidize,  has  short 
heat  range,  and  is  sensitive  to  over- 
firing. 


WILLIAMSVILLE  COAL  COMPANY,  SELBYTOWN 

(See  figure  44) 
Coal  bed — No.   5. 

Thickness  of  floor  clay — Averages  3  feet. 

Sample  19. — Represents  24  inches  of  floor  material ;  medium  soft,  gray  shale 
streaked  with  buff;  contains  carbonaceous  matter  and  granules  of  calcium 
carbonate. 

Slaking  test   Slakes  in  1   hour. 

Residues  left  on  screens — 

10  mesh   0.10% 

20  mesh    0.10% 

60  mesh   4.707c 

100  mesh   0.10% 

120  mesh    0.10% 

Passed  120  mesh  94.907> 

Plasticity   Fair 

Molding  properties  Good 

Drying  properties Warps  and  cracks ;  high-drying  shrinkage. 

Linear  drying  shrinkage 13.18% 

Tempering  water   33.18% 

Oxidation  Difficult,  62%  oxidized  in  9  hours. 

Maximum  safe  burning  temperature  Cone  02 

Heat  range Very  short ;  cracks  in  burning ;  bloats  above  cone  02. 

When  burned  at  cone  02 — 

Burning  shrinkage   7.69% 

Total  shrinkage  20.87% 

Porosity 5.307> 

Fracture     Stony 

Color , Dark  red  ;  scums 

Possibilities  Unsafe  for  manufacture  of  clay  pro- 
ducts as  it  warps  and  cracks  in  dry- 
ing, is  difficult  to  oxidize,  has  short 
heat  range,  cracks  in  burning,  and  is 
sensitive   to   overfiring. 


102 


CLAY  MATERIALS   IN   ILLINOIS   COAL  MINES 


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LABORATORY  TESTS  103 


ILLINOIS  MIDLAND  COAL  COMPANY,   SHERMAN 
(See  figures  45  and  46) 
Depth  of  shaft— 221  feet. 
Coal  bed — No.  5. 

Sample  87. — Location  in  mine,  3d  N.  off  main  W.  200  feet  from  shaft;  sam- 
ple represents  floor  clay  from  7  to  17  inches  below  coal ;  gray-green,  calcareous, 
partly  weathered  (or  slaked)  clay;  contains  carbonaceous  matter  and  altered 
pyrite. 

Slaking  test Practically  complete  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   15.307c 

20  mesh    29.32% 

35  mesh   18.50% 

65  mesh    12.40% 

100  mesh    5.34% 

150  mesh    2.92% 

Passed  150  mesh  16.227* 

Plasticity    Fair 

Molding  properties   Good 

Drying  properties   Good 

Linear  drying  shrinkage    7.017 

Tempering  water   24.007 

Oxidation   Difficult,  727c  oxidized  in   12  hours. 

Maximum  safe  burning  temperature  Cone  08 

Heat  range    Cone  010  to  cone  08 ;  bloats  above  cone  08. 

When  burned  at  cone  08 — 

Burning  shrinkage   7.32% 

Total    shrinkage    14.33% 

Porosity 7.947 

Fracture   Stony 

Color   Light  red 

Possibilities     Doubtful  as  it  is  difficult  to  oxidize,  has 

short   heat    range,   and    is   sensitive   to 
overfiring. 

Sample  88. — Location  of  mine,  same  as  Sample  87;  sample  represents  floor 
material  from  17  to  35  inches  below  coal;  similar  characteristics  to  Sample  87, 
but  contains  considerably  more  finely  distributed  calcium  carbonate. 

Slaking  test    Imperfectly  slaked  at  end  of  test. 

Residues  left   on   screens — 

10  mesh    12817 

20  mesh    32.497* 

35  mesh    32.047* 

65  mesh   9.937 

100  mesh    3.257 

150  mesh    1.737* 

Passed   150  mesh    7.757 

Plasticity    Good 

Molding  properties  Good 

Drying  properties   Cracks 

Linear  drying  shrinkage    6.317' 

Tempering  water    22.007* 

Oxidation Difficult,  847'  oxidized  in  14  hours. 


104  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Maximum  safe  burning  temperature  Cone  01 

Heat  range   Short;  cracks  in  burning;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage   9.26% 

Total   shrinkage    15.57%' 

Porosity     6.61% 

Fracture     Stony 

Color  Pale  red  at  cone  08  to  brown  at  cone  01. 

Possibilities    Not  a  suitable  raw  material  as  it  cracks 

in  drying,  is  difficult  to  oxidize,  has 
short  heat  range,  and  cracks  in  burn- 
ing. 

Sample  107. — Location  in  mine,  3d  off  10  N. ;  sample  represents  floor  ma- 
terial from  5  to  20  inches  below  coal ;  medium  hard,  calcareous,  dark-gray  shale ; 
contains  small  pyrite  concretions  and  carbonaceous  matter  in  the  form  of  plant 
fossils. 

Slaking  test  Slakes  in  13  hours. 

Residues  left  on  screens — 

10  mesh   0.80% 

20  mesh   4.45% 

35  mesh   12.20% 

65  mesh   20.05% 

100  mesh 7.78% 

150  mesh   4.53% 

Passed  150  mesh 50.19% 

Plasticity Good 

Molding   properties    Good 

Drying  properties   Good 

Linear  drying  shrinkage    10.65% 

Tempering  water    31.30% 

Oxidation  Difficult,  37%  oxidized  in  8  hours. 

Maximum  safe  burning  temperature Cone  06 

Heat  range Short;  cracks  in  burning;  bloats  above  cone  06. 

When  burned  at  cone  06— 

Burning  shrinkage   4.90% 

Total   shrinkage    15.55% 

Porosity     10.39% 

Fracture     Stony 

Color Dark  red ;  scums  slightly. 

Possibilities  A  very  unsuitable  material  as  it  is  diffi- 
cult to  oxidize,  cracks  in  burning,  and 
is  sensitive  to  overfiring. 

Sample  108. — Represents  floor  material  from  20  to  30  inches  below  coal ; 
very  similar  in  appearance  to  Sample  107  though  apparently  higher  in  lime. 

Slaking  test  Slakes  in  11  hours. 

Residues  left  on  screens — 

10  mesh   0.89% 

20  mesh   1.46% 

35  mesh   9.13% 

65  mesh   7.89%. 

100  mesh   6.70% 

150  mesh   6.40% 

Passed  150  mesh    67.53% 

Plasticity    Good 

Molding  properties  , Good 


LABORATORY  TESTS  105 

Drying  properties  Good 

Linear  drying  shrinkage   9.96% 

Tempering  water   30.00% 

Oxidation   Difficult ;  55%  oxidized  in  14  hours. 

Maximum   safe  burning  temperature Cone  01 

Heat    range    Very  short ;  cracks  excessively  in  burn- 
ing; bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage 7.56% 

Total   shrinkage    17.52% 

Porosity     4.05% 

Fracture    Dense,   stony. 

Color Light  red  at  cone  04,  brown  at  cone  01 ;  scums. 

Possibilities    , Very  unsuitable  material,  as  it  is  diffi- 

sult  to  oxidize,  has  short  heat  range, 
and  cracks  in  burning. 


MONTOUR  COAL  COMPANY,  MINE  NO.  400,  SPRINGFIELD 
(See  figure  47) 
Depth  of  shaft— 230  feet. 
Coal  bed — No.  5. 

Sample  68. — Location  in  mine,  5th  N.  off  12  W.  off  main  N. ;  sample  rep- 
resents floor  material  from  3  to  25  inches  below  coal ;  medium  hard,  dark-gray 
to  brown  clay;  structure  resembles  that  of  fire  clay;  shows  occasional  slicken- 
sides;  contains  finely  distributed  calcium  carbonate,  a  few  lime  concretions, 
occasional  streaks  of  pyrite,  and  is  high  in  carbon. 

Slaking  test  Slakes  in  7  days. 

Residues  left  on  screens — 

10  mesh   6.17% 

20  mesh   18.85% 

35  mesh   16.04% 

65  mesh   20.31% 

100  mesh   5.96% 

150  mesh    5.30(7c 

Passed  150  mesh  27.37% 

Plasticity   Fair 

Molding  properties Good 

Drying  properties   Cracks 

Linear  drying  shrinkage    8.19% 

Tempering  water    26.10%> 

Oxidation Difficult,  53%  oxidized  in  12  hours. 

Maximum  safe  burning  temperature Cone  06 

Heat  range Very  short ;  cracks  in  burning ;  bloats  above  cone  06. 

When  burned  at  cone  06 — 

Burning  shrinkage    4.72% 

Total    shrinkage    12.91% 

Porosity     6.86% 

Fracture     Stony 

Color    Light   red. 

Possibilities    Of  no  value,  as  it   cracks  in  drying,   is 

difficult  to  oxidize,  has  short  heat 
range,  cracks  in  burning,  and  is  sensi- 
tive to  bloating. 


106 


CLAY  MATERIALS   IN   ILLINOIS   COAL  MINES 


Sample  102. — Location  in  mine,  11th  W.  off  main  N. ;  sample  represents 
floor  material  from  8  to  45  inches  below  coal ;  hard,  calcareous,  dark  greenish- 
gray  clay;  contains  gypsum  and  carbonaceous  matter  as  plant  fossils. 

Slaking  test    Slakes   imperfectly. 

Residues  left  on  screens — 

10  mesh 29.14% 

20  mesh   8.03% 

35  mesh 12.94% 

65  mesh   19.25% 

100  mesh   3.20% 

150  mesh    3.61% 

Passed  150  mesh  23.83% 

Plasticity   Good 


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102,  floor  materials  in  mine  No.  400,  Montour  Coal  Company,  Springfield. 


Molding  properties Good 

Drying  properties  Good 

Linear  drying  shrinkage    7.18% 

Volume  drying  shrinkage 21.70% 

Tempering  water 25.70% 

Oxidation Difficult,  76%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  03 

Heat   range    Short ;    cracks    excessively   in    burning ; 

bloats  above  cone  03. 


LABORATORY  TESTS  107 

When  burned  at  cone  03 — 

Burning    shrinkage 6.89% 

Total    shrinkage    14.16% 

Porosity     8.81% 

Fracture Stony 

Color  Light  cherry  red ;  scums. 

Possibilities  A  very  unsuitable  material,  as  it  is  dif- 
ficult to  oxidize,  cracks  in  burning, 
and  has  short  heat  range. 


SPRINGFIELD    DISTRICT  COAL   MINING   COMPANY,  MINE  NO.    5,    SPRINGFIELD 

(See  figures  48  and  49) 
Depth  of  shaft— 250  feet. 
Coal  bed — No.  5. 

Sample  99. — Location  in  mine,  1st  W.  off  main  S.  1,400  feet  out;  sample 
represents  floor  material  from  0  to  17  inches  below  coal ;  medium  hard,  cal- 
careous, dark,  slate-gray  clay ;  contains  occasional  fragments  nearly  black  in 
color,  showing  slickensides  and  high  in  carbonaceous  matter. 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    50.157? 

20  mesh    21.10% 

35  mesh    9.08% 

65  mesh    6.04% 

100  mesh    3.19% 

150  mesh   2.007* 

Passed  150  mesh  SM% 

Plasticity   Fair 

Molding  properties  Good 

Drying  properties    Warps 

Linear  drying  shrinkage    6.49% 

Tempering  water    22.60% 

Oxidation Difficult,  69%  oxidized  in  13  hours. 

Maximum   safe  burning  temperature Cone  04. 

Heat  range Very  short ;  cracks  in  burning  ;  bloats  above  cone  04. 

When  burned  at  cone  04 — 

Burning  shrinkage   7.31% 

Total  shrinkage  13.80% 

Porosity     8.107c 

Fracture    Dense,    stony. 

Color   Dull  red ;  scums  slightly. 

Possibilities    A   very   unsuitable  material  as   it  warps 

in  drying,  is  difficult  to  oxidize,  has 
short  heat  range,  and  cracks  in  burn- 
ing. 

Sample  100. — Location  in  mine,  same  as  Sample  99;  sample  represents  floor 
material  from  17  to  33  inches  below  coal ;  clay  very  similar  in  character  to  Sam- 
ple 99  except  dark-colored  fragments  are  absent ;  contains  carbonaceous  matter 
as  plant  fossils. 

Slaking  test   Imperfectly  slaked  at  end  of  test. 


108 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  109 

Residues  left  on  screens — 

10  mesh   54.20% 

20  mesh   23.29% 

35  mesh   8.74% 

65  mesh   4.01% 

100  mesh   1.65% 

150  mesh    1.21% 

Passed  150  mesh 6.90% 

Plasticity    Fair 

Molding  properties Good 

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Linear  drying  shrinkage    6.71% 

Tempering  water   22.10% 

Oxidation Difficult,  81  %  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  01 

Heat  range Short ;  cracks  in  burning ;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage   7.75% 

Total   shrinkage    14.46% 

Porosity     0.45% 

Fracture    Dense,    stony. 

Color Dull  red  at  cone  03  to  brown  at  cone  01 ;  scums. 

Possibilities    A  very  unsuitable  material  as  it  is  dif- 
ficult   to    oxidize,    cracks    in    burning, 
and  is  sensitive  to  overfiring. 
Sample  104. — Location  in  mine,  motor   room ;   sample   represents   floor  ma- 
terial from  0  to  18  inches  below  coal;  weathered   (or  partly  slaked)   calcareous 
clay,  dark  greenish-gray  to  black,  streaked  with  yellow;  contains  carbonaceous 
matter,  decomposed  pyrite,  gypsum,  and  sulphur. 

Slaking  test   Slaked  in  13  hours. 

Residues  left  on  screens — 

10  mesh    8.30% 

20  mesh   2.20% 

35  mesh   5.89% 

65  mesh   6\Q% 

100  mesh    4.06% 

150  mesh   2A0r/o 

Passed  150  mesh  7\.05% 

Plasticity   Good 

Molding  properties  Good 

Drying  properties   Warps  and  scums. 

Linear  drying  shrinkage    7.96% 

Tempering  water    28.40% 

Oxidation  Complete  in  8  hours. 

Maximum  safe  burning  temperature Cone  06 

Heat  range Very  short;  cracks  in  burning;  bloats  above  cone  06. 

When  burned  at  cone  06 — 

Burning  shrinkage   10.91  % 

Total   shrinkage    18.87% 

Porosity     11.99% 

Fracture     Stony 

Color   Medium  red  ;   scums. 

Possibilities    Very  unsuitable  material  as  it  warps  in 

drying,    has    short    heat    range,    and 
cracks  in  burning. 


110 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  111 

Sample  105. — Location  in  mine,  same  as  Sample  104 ;  sample  represents  floor 
material  from  18  to  42  inches  below  coal;  partly  weathered  (or  slaked),  slate- 
gray,  calcareous  clay;  contains  decomposed  pyrite,  gypsum,  and  carbonaceous 
matter  as  plant  fossils. 

Slaking  test Imperfectly  slaked  at  end  of  test. 

Residues  left  on  screens — 

10  mesh    6.48% 

20  mesh    11.11% 

35  mesh   26.007^ 

65  mesh   17.92% 

100  mesh    6.22% 

150  mesh   4.36% 

Passed  150  mesh 27.91% 

Plasticity   Fair 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage  8.89% 

Tempering  water   28.50% 

Oxidation Difficult,  72%  oxidized  in   10  hours. 

Maximum  safe  burning  temperature Cone  01 

Heat  range Very  short;  cracks  in  burning;  bloats  above  cone  01. 

When  burned  at  cone  01 — 

Burning  shrinkage   8.51  % 

Total    shrinkage    17.40% 

Porosity     5.04% 

Fracture    Dense,   stony. 

Color Pale  red  ;  scums. 

Possibilities  A  very  unsuitable  material  as  it  is  dif- 
ficult to  oxidize,  cracks  in  burning, 
and  has  short  heat  range. 


SALINE  COUNTY  COAL  COMPANY,   MINK   NO.  2,   HARRISBURG 

(See  figure  50) 
Depth  of  shaft— 96  feet. 
Coal  bed — No.  5. 

Sample  2. — Location  in  mine,  8  E.  main  S. ;  sample  represents  floor  material 
from  1  to  20  inches  below  coal;  in  structure  clay  resembles  that  of  fire  clay; 
shows  well-developed  slickensides ;  contains  carbonaceous  matter  as  plant  fos- 
sils, streaks  of  pyrite,  and  occasional  lime-iron  carbonate  concretions. 

Slaking  test    Slakes    rapidly. 

Residues  left  on  screens — 

10  mesh    51.00% 

20  mesh   25.90% 

60  mesh   13.00% 

100  mesh   2.00%> 

120  mesh    1.00% 

Passed   120  mesh    7.10% 

Plasticity     Medium 

Molding  proporties Good 

1  hying  properties   Good 

Linear  drying  shrinkage  4.44% 

Volume   drying  shrinkage    13.95% 

Tempering  water    17.10% 

Oxidation    Difficult,  92%  oxidized  in  8  hours. 

Maximum  safe  burning  temperature Cone  3 


112  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Heat  range Good,  cone  1  to  possibly  cone  5  or  6. 

When  burned  at  cone  3 — 

Burning  shrinkage   6.74% 

Total   shrinkage    11.18% 

Porosity     3.16% 

Fracture    Vitreous 

Color    From  light  salmon  at  cone  010  to  light 

red  at  cone  01  to  light  brown  at  cone 
3 ;  scums  slightly. 

Possibilities    Common  and   front  brick,  hollow  ware 

(hollow    blocks,     fireproofing,     drain- 
tile,  etc.). 

Precautions Care  must  be  taken  in  burning  during  oxidation. 

Sample  20. — Location  in  mine,  8  E.  main  S. ;  sample  represents  roof  ma- 
terial from  0  to  20  inches  above  coal ;  hard,  slate-gray  shale ;  contains  numerous 
flakes  of  mica  and  dark  streaks  high  in  carbonaceous  matter. 

Slaking  test No  apparent  action  takes  place. 

Residues  left  on  screen Practically  all  left  on  10-mesh  screen. 

Plasticity Low 

Molding  properties Somewhat  troublesome  in  molding. 

Drying  properties Good 

Linear  drying  shrinkage    2.25% 

Tempering  water   14.11% 

Oxidation  Complete  in  8  hours. 

Maximum  safe  burning  temperature Above  cone  3 

Heat  range Cone  01  to  above  cone  3. 

When  burned  at  cone  3 — 

Burning  shrinkage   4.98% 

Total   shrinkage 7.23% 

Porosity     16.88% 

Fracture Coarse,    stony. 

Color  Dark  red ;  very  slight  scumming. 

Possibilities    Common  and  front  brick. 

Precautions    Would   require   thorough   tempering   or 

the  addition  of  a  suitable  plastic  clay 
to  improve  its  molding  properties. 


W.  P.  REND  COLLIERIES  COMPANY,  MINE  NO.   1,  REND 
(See  figure  51) 
Depth  of  shaft— 571  feet. 
Coal  bed— No.  6. 

Sample  35. — Location  in  mine,  face  center  course  E.  main  ^  mile  from 
shaft;  sample  represents  floor  material  from  0  to  30  inches  below  coal;  dark 
gray,  medium  hard  clay  with  structure  resembling  that  of  fire  clay;  irregular 
fracture;  contains  granules  of  altered  pyrite,  carbonaceous  matter  in  streaks, 
and  lime-iron  concretions. 

Slaking  test   Action  rather  slow  and  incomplete. 

Residues  left  on  screens — 

10  mesh    4.94% 

20  mesh 28.60% 

35  mesh   18.68% 

65  mesh   14.50% 

100  mesh   6.99% 

150  mesh   3.87% 

Passed  150  mesh 22.42% 


LABORATORY  TESTS  113 

Plasticity   Fair 

Molding  properties Molds  with  some  difficulty. 

Drying  properties   Good 

Linear  drying  shrinkage    7.53% 

Volume  drying  shrinkage   25.30% 

Tempering  water   18.90% 

Oxidation Difficult,  66%  oxidized  in  14  hours. 

Maximum  safe  burning  temperature Cone  08. 

Heat  range  Very     short ;     bloats     above    cone    08 ; 

cracks    very    badly    in    burning ;    pits 
occur  due  to  lime-iron  granules. 
When  burned  at  cone  08 — 

Burning  shrinkage   4.42% 

Total  shrinkage 11.95% 

Porosity     5.02% 

Fracture     Stony 

Color Dull  light  red ;  scums  slightly. 

Possibilities    Not    a   practical   working   clay   as    it   is 

difficult  to  mold  and  to  oxidize,  cracks 
in  burning,  pits,  and  is  sensitive  to 
bloating. 

Sample  36. — Location  in  mine,  main  W.  200  feet  from  shaft;  sample  repre- 
sents roof  material  from  0  to  36  inches  above  coal;  hard,  blue-gray  shale  that 
breaks  up  into  flat  concretionary  form ;  contains  pyrite  concretions  and  granules 
of  lime-iron  carbonate,  comparatively  free  from  carbon. 

Slaking  test  Very  little  affected  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   : 80.78% 

20  mesh   7.60% 

35  mesh   4.03% 

65  mesh   2.00% 

100  mesh   0.69% 

150  mesh   0.29% 

Passed  150  mesh 4.61% 

Plasticity   Rather  low. 

Molding  properties   Molds  with  some  difficulty. 

Drying  properties   Good 

Linear  drying  shrinkage    3.36% 

Volume  drying  shrinkage    10.94% 

Tempering  water    16.50% 

Oxidation  Complete  in  10  hours. 

Maximum   safe  burning  temperature Cone  04 

Heat  range  Very  short ;   bloats  above   cone  04 ;   oc- 
casional surface  pits  due  to  lime-iron 
granules. 
When  burned  at  cone  04 — 

Burning  shrinkage   7.55% 

Total   shrinkage    10.91% 

Porosity     2.52% 

Fracture    Dense,    stony. 

Color   Dull  dark  red. 

Possibilities     Common  brick ;  not  suitable  for  hollow 

blocks  because  of  molding  difficulties. 
Precautions   Would  require  thorough  tempering. 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  115 


SESSER  COAL  COMPANY,   SESSER  MINE,   SESSER 
(See  figure  52) 
Depth  of  shaft— 647  feet. 
Coal  bed — No.  6. 

Sample  7. — Represents  floor  material  below  coal ;  medium  hard  gray  clay 
with  structure  resembling  that  of  fire  clay;  shows  slickensides ;  contains  car- 
bonaceous matter  as  plant  fossils  and  in  thin  seams,  no  concretions  or  pyrite 
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Slaking  test Slakes  slowly. 

Residues  left  on  screens — 

10  mesh    3.60% 

20  mesh   0.38$ 

60  mesh   0.29',' 

100  mesh    0  19% 

120  mesh   0.00' ; 

Passed  120  mesh 95.54'  < 

Plasticity    Fair 

Molding  properties  Good 

Drying  properties    Good 

Linear  drying  shrinkage    5.60'  ( 

Tempering   water    20.32% 

Oxidation   Difficult,  84%    oxidized  in  9  hours. 

Maximum  safe  burning   temperature Above  cone  3 

Heat  range ("one  1  to  above  cone  3. 

When  burned  at  cone  3 — 

Burning  shrinkage   6.94(  < 

T\  »tal    shrinkage    12.54' , 

Porosity     3.40'  \ 

Fracture     Stony 

Color    Light    salmon    at    cone   010,   lijjit    red    at 

cone  02.   light   brown  at   cone   1. 

Possibilities    Common   and    front  brick,  hollow    ware. 

Precautions Requires  care  during  the  oxidizing  period  of  the  burn. 


CARTERVILLE  &   HERRIN  COAL  COMPANY,  JEFFREY    MINE,   HERRIN 
(See  figure  53) 
Depth  of  shaft— 134  feet. 
Coal  bed — No.  6. 

Sample  SI. — Location  in  mine,  100  feet  southwest  of  shaft;  sample  repre- 
sents floor  material  below  coal;  calcareous  clay  with  structure  resembling  that 
of  fire  clay;  occasional  slickensides;  contains  streaks  of  iron  oxide  and  finely 
distributed  carbon  in  spots. 

Slaking   test    Slakes    in    147   hours. 

Residues  left  on   screens — 

10  mesh    5.95', 

20  mesh    14.359! 

35  mesh   18.469? 

65  mesh   21.9095 

100  mesh   9.99'  \ 

150  mesh    5.00^5 

Passed    150  mesh    26.3595 


116 


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LABORATORY  TESTS  117 

Plasticity    Fair 

Molding  properties  Good 

Drying  properties   Good 

Linear  drying  shrinkage    7.33% 

Volume  drying  shrinkage    21.40% 

Tempering  water   21.60% 

Oxidation  Difficult,  84%  oxidized  in  14  hours. 

Maximum   safe  burning  temperature Cone  04 

Heat  range   Cone  06  to  cone  04 ;  cracks  in  burning ; 

bloats  above  cone  04. 
When  burned  at  cone  04 — 

Burning  shrinkage   6.59% 

Total    shrinkage    13.92% 

Porosity     4.59% 

Fracture    Irregular,    stony. 

Color Pale  red  to  light  green  brown ;  scums. 

Possibilities    Not    suitable    material    as    it   is    difficult 

to  oxidize  and  cracks  in  burning. 


BRINKLEY  &  MILES,  MARION 
(See  figure  54) 
Kind  of  mine — Stripping. 
Coal  bed — No.  6. 

Sample  32. — Represents  floor  material  from  1  to  18  inches  below  coal ;  med- 
ium hard,  light-gray,  calcareous  shale,  brown  in  spots  and  streaks;  contains 
carbonaceous  matter  as  plant  fossils  and  concretions  of  calcium  carbonate. 

Slaking  test    Slakes  in   13  hours. 

Residues  left  on  screens — 

10  mesh    3.89$ 

20  mesh   5.48% 

35  mesh    6.17% 

65  mesh    3.15% 

100  mesh    1.19% 

150  mesh    1.51% 

Passed    150  mesh    78.61% 

Plasticity    Good 

Molding   properties    Good 

Drying  properties    Cracks 

Linear  drying  shrinkage    7.46% 

Volume  drying  shrinkage    26.80% 

Tempering   water 21.30% 

Oxidation   Difficult,  82%  oxidized  in  14  hours. 

Heat  range   Very  short ;  cracks  in  burning  ;   surface 

pits ;  bloats  above  cone  04. 
When  burned  at  cone  04 — ■ 

Burning  shrinkage   6.06*  < 

Total    shrinkage    13.52% 

Porosity     2.31% 

Fracture    Dense,    stony. 

Color  Light  red  to  brown. 

Possibilities     A  very  unsuitable  material  as  it  cracks 

in  burning  and  in  drying,  is  difficult 
to  oxidize,  has  short  heat  range,  and 
pits  due  to  lime  granules. 


118 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  119 


SHOAL  CREEK  COAL  COMPANY,  MINE  NO.   1,  PANAMA 
(See  figure  55) 
Depth  of  shaft— 374  feet. 
Coal   bed— No.   6. 

Sample  13. — Represents  floor  material  below  coal ;  medium  hard,  calcareous, 
light-gray  shale ;  contains  small  iron  carbonate  nodules,  gypsum,  and  calcareous 
matter  as   plant    fossils. 

Slaking  test   Slakes  very  slowly. 

Residues  left  on   screens — 

10  mesh   6.907a 

20  mesh    2.50% 

60  mesh   3.80% 

100  mesh   0.70% 

120  mesh    0.00% 

Passed  120  mesh  86.10% 

Plasticity   Fair 

Molding   properties    Good 

Drying  properties   Warps,  drying  shrinkage  high 

Linear  drying  shrinkage 15.38% 

Tempering  water   37.95% 

Oxidation  Difficult,  60%  oxidized  in  9  hours. 

Maximum  safe  burning  temperature    Cone  06 

Heat  range  Short ;  cracks  in  burning ;  bloats. 

When  burned  at  cone  06 — 

Burning    shrinkage    5.69% 

Total   shrinkage    21.07% 

Porosity     1.99% 

Fracture     Stony 

Color   Light   red  ;   scums  excessively. 

Possibilities    A  very  unsuitable  material  as  it  warps 

in  drying,  is  difficult  to  oxidize,  has 
short  heat  range;  cracks  in  burning, 
is  sensitive  to  overfiring,  and  scums 
excessively. 


BRILLIANT  COAL  COMPANY,  HORN    MINK,   DUQUOIN 

(See  figure  56) 
Depth  of  shaft— 75  feet. 
Coal  bed — No.  6. 

Average  thickness  of  roof — 15  to  20  feet. 

Sample  23. — Represents  roof  material  above  coal ;  hard,  blue-gray  shale 
easily  separated  into  plates  about  Y$  inch  thick;  contains  brown  iron  streaks, 
otherwise  comparatively  uniform  in  appearance. 

No  slaking  and  screening  tests  were  made. 

Plasticity    Fair 

Drying  properties   Good 

Linear  drying  shrinkage    3.41  % 

Tempering  water   18.48% 

Oxidation  Complete  in  3  hours. 

Maximum  safe  burning  temperature Above  cone  3. 

Heat  range   Cone  1  to  above  cone  3. 


120 


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LABORATORY  TESTS  121 

When  burned  at  cone  3 — 

Burning  shrinkage    8.55% 

Total    shrinkage    11.96% 

Porosity     2.69% 

Fracture    Smooth,  dull. 

Color   Dark  red  ;   scums  slightly. 

Possibilities Common,   front,  and  paving  brick,  hollow  ware. 


PARADISE  COAL  COMPANY,   PARADISE   MINE,  DUQUOIN 
(See  figure  57) 
Depth  of  shaft— 371  feet. 
Coal  bed— No.  6. 

Sample  I. — Location  of  sample,  room  1  NE. ;  sample  represents  roof  ma- 
terial from  0  to  24  inches  above  coal ;  hard,  dark-gray  shale  ;  contains  a  little 
calcium  carbonate  and  occasional  lime-iron  carbonate  concretions,  comparatively 
free  from  carbon. 

Slaking  test   No  shaking  action  noticeable. 

Residues  left  on  screens.  .  .Practically  all  was  left  on  10-mesh  screen. 

Plasticity    Rather  low. 

Molding  properties Molds  without   serious  difficulties. 

Drying  properties   Good 

Linear  drying  shrinkage    3.69% 

Volume  drying  shrinkage    11.227 

Tempering  water    16.10% 

Oxidation   Complete  in  5  hours. 

Maximum   safe  burning   temperature Cone  1 

Heat  range   Short ;  bloats  above  cone  1. 

When  burned  at  cone  1 — 

Burning  shrinkage    5.50% 

Total    shrinkage    9.19% 

Porosity     10.817 

Fracture     Stom 

Color  Dull  red  ;  scums  slightly. 

Possibilities    Common  and   front  brick. 

Precautions     Should   be   thoroughly    tempered    to  de- 
velop good  molding  plasticity. 


PIONEER  COAL  COMPANY,   BELLEVILLE 

(See  figure  58) 
Depth  of  shaft— 51  feet. 
Thickness  of  floor  clay — Variable. 
Coal  bed— No.  6. 

Sample  92. — Location  in  mine,  3d  E. ;  sample  represents  floor  material  from 
0  to  16  inches  below  coal  (taken  down  to  pebble  layer)  ;  a  mixture  of  light- 
gray  and  blue-gray  shale,  partly  weathered  (or  slaked)  ;  contains  considerable 
carbonaceous  matter,  partly  decomposed  pyrite,  and  sulphur. 

Slaking  test   Slakes  in   1 1  hours. 


122  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Residues  left  on  screens — 

10  mesh   0.06% 

20  mesh   0.15% 

35  mesh  1.32% 

65  mesh 3.43% 

100  mesh   3.11% 

150  mesh   3.18% 

Passed   150  mesh    88.75% 

Plasticity   Fair 

Molding  properties    Good 

Drying  properties   Good 

Linear  drying  shrinkage 9.54% 

Tempering  water   21.20% 

Oxidation  Difficult,  70%  oxidized  in  13  hours. 

Maximum  safe  burning  temperature       Cone  06 

Heat  range  Cone  08  to  cone  06 ;  bloats  above  cone 

06;  cracks  in  burning. 
When  burned  at  cone  06 — 

Burning  shrinkage   6.93% 

Total   shrinkage    16.47% 

Porosity     2.95% 

Fracture    Vitreous 

Color  Medium  red. 

Possibilities    Not  a  suitable  material  as  it  is  difficult 

to  oxidize,   cracks  in  burning,   and  is 
sensitive  to  overfiring  and  bloating. 

Sample  ioi. — Locaton  in  mine,  E.  entry;  sample  represents  floor  material 
from  0  to  28  inches  below  coal  (taken  down  to  pebble  layer)  ;  sample  had  been 
wet  and  partly  slaked ;  contains  considerable  carcareous  and  carbonaceous  mat- 
ter and  apparently  decomposed  pyrite,  gives  test  for  calcium  sulphate. 

Slaking  test   Slakes  in  13  hours. 

Residues  left  on  screens — 

10  mesh   0.46% 

20  mesh   0.61% 

35  mesh   1.65% 

65  mesh   5.60% 

100  mesh   4.24% 

150  mesh   - 3.27% 

Passed  150  mesh  84.17% 

Plasticity   Good 

Molding  properties    Good 

Drying  properties    Warps 

Linear  drying  shrinkage    1 1.37% 

Tempering  water    31.60% 

Oxidation    No  trials  made. 

Maximum  safe  burning  temperature Cone  08 

Heat  range Short ;  very  sensitive  to  overfiring  and  bloating. 

When  burned  at  cone  08— 

Burning  shrinkage   5.88% 

Total   shrinkage    17.25% 

Porosity     2.00% 

Fracture    Dense,   stony. 

Color   Pale  red ;  scums  excessively. 

Possibilities    A  very  unsuitable  material  as  it  warps 

in    drying,    is    sensitive    to    overfiring, 
and  scums  excessively. 


LABORATORY  TESTS  123 


MULBERRY  HILL  COAL  COMPANY,  MINE  NO.  2,   FREEBURG 
(See  figure  59) 
Depth  of  shaft— 150  feet. 
Coal  bed — No.  6. 

Sample  82. — Location  in  mine,  100  feet  out  on  main  W. ;  sample  represents 
floor  material  from  0  to  33  inches  below  coal ;  light-gray,  medium  soft,  cal- 
careous clay;  contains  small  granules  of  calcium  carbonate,  streaks  of  carbon- 
aceous matter,  and  calcium  sulphate. 

Slaking  test Slakes  in  11  hours. 

Residues  left  on  screens — 

10  mesh    15.50% 

20  mesh   0.90% 

35  mesh   1.44% 

65  mesh   1.48% 

100  mesh   0.90% 

150  mesh   0.70% 

Passed   150  mesh    79.08% 

Plasticity    Good 

Molding  properties    Good 

Drying  properties   Good 

Linear  drying  shrinkage 9.22% 

Tempering  water   28.80% 

Oxidation  Difficult,  76%  oxidized  in  13  hours. 

Heat  range Cone  08  to  cone  06;  cracks  in  burning ;  surface  pits. 

When  burned  at  cone  06 — 

Burning  shrinkage   3.90% 

Total    shrinkage    13.12% 

Porosity     10.24% 

Fracture     Stony 

Color   Pale  red  ;   scums  excessively. 

Possibilities  A  very  unsuitable  material  as  it  is  dif- 
ficult to  oxidize,  pits,  cracks  in  burn- 
ing, and  scums  excessively. 


KOLB  COAL  COMPANY,  MINE  NO.  2,  MASCOUTAH 

( See  figure  60) 
Depth   of  shaft— 168    feet. 
Coal  bed— No.  6. 

Sample  83. — Location  in  mine,  sump  under  air  shaft;  sample  represents 
floor  material  from  0  to  24  inches  below  coal ;  gray-green,  medium  hard,  cal- 
careous clay;  contains  pyrite  nodules,  calcium  carbonate  concretions,  and  streaks 
of  carbonaceous  matter. 

Slaking  test   Slakes  in   1 1   hours. 

Residues  left  on  screens — 

10  mesh   0.78% 

20  mesh    0.57% 

35  mesh   0.88% 

65  mesh   1.20% 

100  mesh   0.79% 

150  mesh    0.64% 

Passed   150  mesh    95.86% 

Plasticity    Good 

Molding   properties    Good 


124 


CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


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LABORATORY  TESTS  125 

Drying  properties   Good 

Linear  drying  shrinkage 10.20% 

Tempering  water   29.10% 

Oxidation  Difficult,  53%  oxidized  in  12  hours. 

Maximum   safe  burning  temperature Cone  08 

Heat   range    Cone  010  to  cone  08 ;  bloats  above  cone 

08 ;  surface  pits  are  profuse. 
When  burned  at  cone  08 — 

Burning  shrinkage   5.35% 

Total    shrinkage    15.55% 

Porosity     1.797c 

Fracture    Vitreous 

Color  Light  red ;  scums. 

Possibilities    Not    a    suitable    raw    material    as    it    is 

difficult  to  oxidize,  has  short  heat 
range,  is  sensitive  to  overfiring,  and 
pits. 

Sample  86. — Location  in  mine,  same  as  Sample  85 ;  sample  represents  floor 
material  from  24  to  48  inches  below  coal ;  characteristics  similar  to  Sample  85 
except  that  it  shows  white  patches  of  calcium  carbonate  and  more  calcium  car- 
bonate concretions. 

Slaking  test   Slakes  in  1 1  hours. 

Residues  left  on  screens — 

10  mesh   10.17% 

20  mesh   0.45% 

35  mesh   0.57% 

65  mesh   0  52% 

100  mesh   0.35% 

150  mesh   0.17% 

Passed  150  mesh    87.77%, 

Plasticity    Good 

Molding   properties    Good 

Drying  properties   Good 

Linear  drying  shrinkage    9.04%> 

Tempering  water    28.70% 

Oxidation   Difficult,  76'  '<   oxidized  in  14  hours. 

Maximum   safe   burning  temperature Cone  06 

Heat    range    Cone  08  to  cone  06 ;  cracks  in  burning  ; 

surface    pits    profusely    due    to    lime, 
granules. 
When  burned  at  cone  06 — 

Burning  shrinkage   4.06% 

Total    shrinkage    13.10% 

Porosity     9.68% 

Fracture    Dense,   stony 

Color   Pale  red ;  scums  excessively. 

Possibilities    Not  a  suitable  material  as  it  is  difficult 

to  oxidize,  cracks  in  burning,  pits, 
and  scums  excessively. 


126  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 


JOSEPH  TAYLOR  COAL  COMPANY,  TAYLOR  MINE,  O'FALLON 
(See  figure  61) 
Depth  of  shaft— 200  feet. 
Coal  bed— No.  6. 

Thickness  of  floor  clay — Reported  to  be  7  feet. 

Sample  3. — Location  in  mine,  2d  N.  off  E. ;  sample  represents  floor  ma- 
terial from  0  to  48  inches  below  coal ;  soft  gray  shale ;  contains  carbonaceous 
matter  as  plant  fossils  and  a  small  amount  of  calcium  carbonate. 

Slaking  test   Slakes   rapidly   to   a   plastic   mass   with 

very  little  granular  matter. 
No  screening  tests  made. 

Plasticity   Very  high. 

Molding  properties A  little  too  plastic  to  mold  well. 

Drying  properties.  .Warps  and  tends  to  crack;  high-drying  shrinkage. 

Linear  drying  shrinkage    14.29% 

Tempering  water   38.20% 

Oxidation  Difficult,  65%  oxidized  in  8  hours. 

Maximum  safe  burning  temperature Cone  06 

Heat  range Very  short;  bloats  above  cone  06;  cracks  in  burning. 

When  burned  at  cone  06 — 

Burning  shrinkage   8.28% 

Total   shrinkage    22.57% 

Porosity     1.14% 

Fracture    Vitreous 

Color   Dark  red ;  scums  slightly. 

Possibilities  Not  a  suitable  material  as  it  has  ex- 
cessive plasticity,  warps  and  cracks 
in  drying,  is  difficult  to  oxidize,  has 
short  heat  range,  and  cracks  in  burn- 
ing. 


AUBURN  &  ALTON  COAL  COMPANY,  AUBURN 
(See  figure  62) 
Depth  of  shaft— 268  feet. 
Coal  bed— No.  6. 

Thickness  of  floor — Irregular,  8  feet  thick  at  sump. 

Sample  81. — Location  in  mine,  2,800  feet  east  of  shaft;  sample  represents 
floor  material  from  2  to  23  inches  below  coal ;  light-gray  sandy  clay  streaked 
with  yellow ;  contains  mica  and  streaks  of  carbon. 

Slaking  test Action  complete  at  end  of  test. 

Residues  left  on  screens — 

10  mesh   5.67% 

20  mesh   2.17% 

35  mesh   2.64% 

65  mesh  7.55% 

100  mesh  11.49% 

150  mesh   6.52% 

Passed   150  mesh    63.96% 

Plasticity   Fair 

Molding   properties    Good 


LABORATORY  TESTS 


127 


Drying  properties   ^°°rt 

Linear  drying  shrinkage    4.41% 

Volume  drying  shrinkage   13.80% 

Tempering  water   19.20% 

Oxidation Complete  in  4  hours. 

Maximum  safe  burning  temperature Above  cone  5. 

Heat  range. .  .Temperature  not  carried  high  enough  to  determine  this. 

When  burned  at  cone  5 — 

Burning  shrinkage   6.51% 

Total   shrinkage    10.92% 

Porosity     14.88% 

Fracture     Stony 

Color  Salmon  at  cone  010,  brownish  gray  at  cone  5. 

Possibilities   Common  and  front  brick. 

36 


1        1        |       No.  95               1 
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floor  materials  in  the  mine  of  Auburn  &  Alton  Coal  Company,  Auburn. 


Sample  95. — Location  in  mine,  300  feet  from  shaft  back  E.  entry;  sample 
represents  25  inches  of  floor  material  beginning  a  few  inches  below  coal;  sam- 
ple had  been  wet  and  partly  slaked ;  contains  pyrite  nodules,  carbonaceous  mat- 
ter, sulphur,  and  iron  sulphate. 

Slaking  test   Slakes  in  1 1  hours. 

Residues  left  on  screens — 

10  mesh   0.70% 

20  mesh   1.55% 

35  mesh   5.09% 

65  mesh   9.16% 

100  mesh    5.04% 

150  mesh   2.75% 

Passed   150  mesh    75.71% 


128  CLAY  MATERIALS  IN  ILLINOIS  COAL  MINES 

Plasticity   Good 

Molding   properties    Good 

Drying  properties  Good 

Linear  drying  shrinkage    5.88% 

Volume  drying  shrinkage   18.60% 

Tempering  water   23.00% 

Oxidation    Complete  in  6  hours. 

Maximum   safe  burning  temperature Cone  3 

Heat  range  Cone  1  to  cone  3. 

When  burned  at  cone  3 — 

Burning  shrinkage   , 7.23% 

Total   shrinkage    13.11% 

Porosity     7.44% 

Fracture     : .     Stony 

Color Dark  velvet-red  surface,  dark  red  fracture. 

Possibilities    Common  and  front  brick. 


INDEX 


PAGE 

Alden     Coal     Company,     tests     of 

clays    from    75-79 

Athens,  tests  of  clays   from 91-93 

Auburn    &    Alton    Coal    Company, 

tests  of  clays  from 126-128 


Barium   salts,   addition   of 16 

Barr  Brick  Company,  test  of  clay 

from    37 

Bloating  during  burning 16-17 

Bloomington,  tests  of  clays  from. 87-90 
Brilliant    Coal    Company,    test    of 

clay  from   119-121 

Brinkley  &  Miles,  test  of  clay  from  117 

Briquets,    molding    of 19,  25-27 

Burlington     Paving     Brick     Com- 
pany, test  of  clay  from 37 

Burning  process    12-18,  22-23,  27 

Burning  shrinkage    23 


Calcium    sulphate,    effect    of 16 

Cantrall    Cooperative    Coal    Com- 
pany, test  of  clay  from. ..  .99-101 
Carterville    &    Herrin    Coal    Com- 
pany, test  of  clay  from. .  .  .  115-117 

Cherry,  tests  of  clays  from 39-41 

Chicago,  Wilmington  &  Vermilion 
Coal   Company,   tests   of   clays 

from    49-53 

Christian     County,     character     of 

clays  in   32 

Clark  Coal  &  Coke  Company,  tests 

of  clays  from   93-94 

Clay,  general  character  of 10 

Clinton  County,  character  of  clays 

in    32 

Coal  City,  tests  of  clays  from 47^9 

Coal  Valley,  tests  of  clays  from.  .79-82 
Colchester   Coal  &    Manufacturing 

Company,  test  of  clay  from..     73 
Colliers    Cooperative    Coal    Com- 
pany, tests  of  clays  from 97-99 

Common   brick,   character   of   clay 

for    11-12,15 

Crescent   Coal    Company,   tests   of 

clays    from    95-96 


Dalzell,  tests  of  clays   from 41-44 

Decatur    Coal    Company,    test    of 

clay    from    86 


PAGE 

Decatur,  tests  of  clays  from. ..  .83-85 
Districts,  character  of  clays  by.. 28-32 
Duquoin,  tests  of  clays  from.  .119-121 

F 

Fireproofing,  character  of  clay  for     12 

Floor  clays,  character  of 30-32 

Franklin     County,     character     of 

clays    in    32 

Freeburg,  test  of  clay  from 123 

Front  brick,  character  of  clay  for  12,  14 

G 

Galesburg,  test  of  clay  from....  37 
Gray  &  Jones  Coal  Company,  tests 

of   clays    from    60-65 

Grinding  of   samples 25 

H 

Hand-plunger  machine,  diagram  of  26 
Harrisburg,  tests  of  clays  from  111-112 

Heat  range    15-16 

Herrin,  test  of  clay  from 115-117 

Hollow    ware,    character    of    clay 

for    12,15 


Illinois     Clay     Company,     test     of 

clay  from  38-39 

Illinois    Midland    Coal    Company, 

tests  of  clays  from 103-107 

Illinois     Valley     Coal     Company, 

tests  of  clays  from 65-68 

Illinois    Zinc    Company,    tests    of 

clays    from 57-59 


Joseph     Taylor     Coal     Company, 

test  of  clay  from 126 

K 

Kolb  Coal  Company,  tests  of  clays 
from     123-125 


Laboratory   tests,    importance 

of  11,18-30,  27-128 

La  Salle      County      Carbon      Coal 

Co.,  tests  of  clays  from 53-56 

Linear  drying  shrinkage 22 

M 

McLean  County  Coal  Company, 
tests  of  clays   from 87-90 

Macoupin     County,     character     of 

clays    in    32 


(129) 


130 


INDEX — Continued 


PAGE 

Madison     County,     character     of 

clays   in    32 

Manufacturers  &  Consumers  Coal 
Company,  tests  of  clays  from.83-85 

Marion,  test  of  clay  from 117 

Marion  County,  character  of  clays 

in    32 

Marquette  Third  Vein  Coal  Com- 
pany, tests  of  clays  from. . .  .44-45 

Mascoutah,  tests  of  clays  from. 123-125 

Matthiessen  &  Hegeler  Zinc  Com- 
pany, tests  of  clays  from 56 

Matherville,  tests  of  clays  from.  .75-79 

Minonk    Coal    Company,    tests    of 

clays    from    71-73 

Montgomery  County,  character  of 

clays    in    32 

Moultrie     County,     character     of 

clays  in  32 

Mulberry  Hill  Coal  Company,  test 
of  clay  from  123 

N 
Niantic,  test  of  clay  from 86 

O 

O'Fallon,  test  of  clay  from 126 

Oglesby,    tests   of   clays    from 

38-39,  57-60 

Oglesby    Coal    Company,    test    of 

clay    from    60 

Oxidation     12,  19-21 

P 

Panama,  test  of  clay  from 119 

Paradise    Coal    Company,    test    of 

clay    from    121 

Paving    brick,    character    of    clay 

for    12,  14 

Peoria,  tests  of  clays  from 93-96 

Perry   County,   character   of   clays 

in    32 

Pioneer    Coal    Company,    tests    of 

clays    from    121-122 

Pitting  during  burning 13,  16 

Porosity   of   clays 13-14,  23 

Pryce  Coal  Company,  tests  of  clays 

from    79-82 

R 

Randolph     County,     character     of 

clays    in    32 

Rend,  tests  of  clays  from 112-113 

Roof  shales,  character  of 30-32 


S 

PAGE 

St.     Clair     County,     character     of  - 

clays  in   32 

St.   Paul   Coal   Company,   tests   of 

clays    from    39-41 

Saline      County      Coal     Company, 

tests  of  clays  from 111-112 

Sangamon    County,    character    of 

clays    in    32 

Screening   tests    27 

Scumming    . 16-18 

Selbytown,  test  of  clay  from 101 

Seneca,  tests  of  clays  from 60-65 

Sesser  Coal  Company,  test  of  clay 

from    115 

Shelby  County,  character  of  clays 

in    32 

Sherman,  tests  of  clays  from.  .103-107 
Shoal    Creek    Coal    Company,   test 

of    clay    from 119 

Slaking  test 18-19 

South    Bartonville,    tests    of    clays 

from    97-99 

South   Wilmington,   tests   of   clays 

from    49-53 

Sparland,  tests  of  clays  from. ..  .65-68 
Springfield    District    Coal    Mining 

Company,  tests  of  clays  from. 

107-111 

Spring     Valley      Coal      Company, 

tests  of  clays  from 41-44 

Stiff-mud  process    18 

Streator,  test  of  clay  from 37 

T 

Tempering  water  22 

V 

Valentine  Farm  mine,  test  of  clay 

from     73-75 

Volume  shrinkage  22 

W 

Wabash    Coal    Company,    tests    of 

clays    from    91-93 

Washington   County,   character   of 

clays  in  32 

Wenona    Coal    Company,    tests    of 

clays    from    68-70 

Williamson    County,    character    of 

clays  in   32 

Williamsville    Coal   Company,   test 

of  clay  from 101 

W.    P.   Rend   Collieries    Company, 

tests  of  clays  from 112-113 


